AstBuilder.scala

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.spark.sql.catalyst.parser

import java.util.Locale
import javax.xml.bind.DatatypeConverter

import scala.collection.JavaConverters._
import scala.collection.mutable.ArrayBuffer

import org.antlr.v4.runtime.{ParserRuleContext, Token}
import org.antlr.v4.runtime.tree.{ParseTree, RuleNode, TerminalNode}

import org.apache.spark.internal.Logging
import org.apache.spark.sql.AnalysisException
import org.apache.spark.sql.catalyst.{FunctionIdentifier, TableIdentifier}
import org.apache.spark.sql.catalyst.analysis._
import org.apache.spark.sql.catalyst.catalog.{BucketSpec, CatalogStorageFormat}
import org.apache.spark.sql.catalyst.expressions._
import org.apache.spark.sql.catalyst.expressions.aggregate.{First, Last}
import org.apache.spark.sql.catalyst.parser.SqlBaseParser._
import org.apache.spark.sql.catalyst.plans._
import org.apache.spark.sql.catalyst.plans.logical._
import org.apache.spark.sql.catalyst.plans.logical.sql.{AlterTableAddColumnsStatement, AlterTableAlterColumnStatement, AlterTableDropColumnsStatement, AlterTableRenameColumnStatement, AlterTableSetLocationStatement, AlterTableSetPropertiesStatement, AlterTableUnsetPropertiesStatement, AlterViewSetPropertiesStatement, AlterViewUnsetPropertiesStatement, CreateTableAsSelectStatement, CreateTableStatement, DeleteFromStatement, DescribeColumnStatement, DescribeTableStatement, DropTableStatement, DropViewStatement, InsertIntoStatement, QualifiedColType, ReplaceTableAsSelectStatement, ReplaceTableStatement, ShowNamespacesStatement, ShowTablesStatement, UpdateTableStatement, UseStatement}
import org.apache.spark.sql.catalyst.util.DateTimeUtils.{getZoneId, stringToDate, stringToTimestamp}
import org.apache.spark.sql.connector.expressions.{ApplyTransform, BucketTransform, DaysTransform, Expression => V2Expression, FieldReference, HoursTransform, IdentityTransform, LiteralValue, MonthsTransform, Transform, YearsTransform}
import org.apache.spark.sql.internal.SQLConf
import org.apache.spark.sql.types._
import org.apache.spark.unsafe.types.{CalendarInterval, UTF8String}
import org.apache.spark.util.random.RandomSampler

/**
 * The AstBuilder converts an ANTLR4 ParseTree into a catalyst Expression, LogicalPlan or
 * TableIdentifier.
 */
class AstBuilder(conf: SQLConf) extends SqlBaseBaseVisitor[AnyRef] with Logging {
  import ParserUtils._

  def this() = this(new SQLConf())

  protected def typedVisit[T](ctx: ParseTree): T = {
    ctx.accept(this).asInstanceOf[T]
  }

  /**
   * Override the default behavior for all visit methods. This will only return a non-null result
   * when the context has only one child. This is done because there is no generic method to
   * combine the results of the context children. In all other cases null is returned.
   */
  override def visitChildren(node: RuleNode): AnyRef = {
    if (node.getChildCount == 1) {
      node.getChild(0).accept(this)
    } else {
      null
    }
  }

  override def visitSingleStatement(ctx: SingleStatementContext): LogicalPlan = withOrigin(ctx) {
    visit(ctx.statement).asInstanceOf[LogicalPlan]
  }

  override def visitSingleExpression(ctx: SingleExpressionContext): Expression = withOrigin(ctx) {
    visitNamedExpression(ctx.namedExpression)
  }

  override def visitSingleTableIdentifier(
      ctx: SingleTableIdentifierContext): TableIdentifier = withOrigin(ctx) {
    visitTableIdentifier(ctx.tableIdentifier)
  }

  override def visitSingleFunctionIdentifier(
      ctx: SingleFunctionIdentifierContext): FunctionIdentifier = withOrigin(ctx) {
    visitFunctionIdentifier(ctx.functionIdentifier)
  }

  override def visitSingleMultipartIdentifier(
      ctx: SingleMultipartIdentifierContext): Seq[String] = withOrigin(ctx) {
    visitMultipartIdentifier(ctx.multipartIdentifier)
  }

  override def visitSingleDataType(ctx: SingleDataTypeContext): DataType = withOrigin(ctx) {
    visitSparkDataType(ctx.dataType)
  }

  override def visitSingleTableSchema(ctx: SingleTableSchemaContext): StructType = {
    withOrigin(ctx)(StructType(visitColTypeList(ctx.colTypeList)))
  }

  /* ********************************************************************************************
   * Plan parsing
   * ******************************************************************************************** */
  protected def plan(tree: ParserRuleContext): LogicalPlan = typedVisit(tree)

  /**
   * Create a top-level plan with Common Table Expressions.
   */
  override def visitQuery(ctx: QueryContext): LogicalPlan = withOrigin(ctx) {
    val query = plan(ctx.queryTerm).optionalMap(ctx.queryOrganization)(withQueryResultClauses)

    // Apply CTEs
    query.optionalMap(ctx.ctes)(withCTE)
  }

  override def visitDmlStatement(ctx: DmlStatementContext): AnyRef = withOrigin(ctx) {
    val dmlStmt = plan(ctx.dmlStatementNoWith)
    // Apply CTEs
    dmlStmt.optionalMap(ctx.ctes)(withCTE)
  }

  private def withCTE(ctx: CtesContext, plan: LogicalPlan): LogicalPlan = {
    val ctes = ctx.namedQuery.asScala.map { nCtx =>
      val namedQuery = visitNamedQuery(nCtx)
      (namedQuery.alias, namedQuery)
    }
    // Check for duplicate names.
    val duplicates = ctes.groupBy(_._1).filter(_._2.size > 1).keys
    if (duplicates.nonEmpty) {
      throw new ParseException(
        s"CTE definition can't have duplicate names: ${duplicates.mkString("'", "', '", "'")}.",
        ctx)
    }
    With(plan, ctes)
  }

  /**
   * Create a logical query plan for a hive-style FROM statement body.
   */
  private def withFromStatementBody(
      ctx: FromStatementBodyContext, plan: LogicalPlan): LogicalPlan = withOrigin(ctx) {
    // two cases for transforms and selects
    if (ctx.transformClause != null) {
      withTransformQuerySpecification(
        ctx,
        ctx.transformClause,
        ctx.whereClause,
        plan
      )
    } else {
      withSelectQuerySpecification(
        ctx,
        ctx.selectClause,
        ctx.lateralView,
        ctx.whereClause,
        ctx.aggregationClause,
        ctx.havingClause,
        ctx.windowClause,
        plan
      )
    }
  }

  override def visitFromStatement(ctx: FromStatementContext): LogicalPlan = withOrigin(ctx) {
    val from = visitFromClause(ctx.fromClause)
    val selects = ctx.fromStatementBody.asScala.map { body =>
      withFromStatementBody(body, from).
        // Add organization statements.
        optionalMap(body.queryOrganization)(withQueryResultClauses)
    }
    // If there are multiple SELECT just UNION them together into one query.
    if (selects.length == 1) {
      selects.head
    } else {
      Union(selects)
    }
  }

  /**
   * Create a named logical plan.
   *
   * This is only used for Common Table Expressions.
   */
  override def visitNamedQuery(ctx: NamedQueryContext): SubqueryAlias = withOrigin(ctx) {
    val subQuery: LogicalPlan = plan(ctx.query).optionalMap(ctx.columnAliases)(
      (columnAliases, plan) =>
        UnresolvedSubqueryColumnAliases(visitIdentifierList(columnAliases), plan)
    )
    SubqueryAlias(ctx.name.getText, subQuery)
  }

  /**
   * Create a logical plan which allows for multiple inserts using one 'from' statement. These
   * queries have the following SQL form:
   * {{{
   *   [WITH cte...]?
   *   FROM src
   *   [INSERT INTO tbl1 SELECT *]+
   * }}}
   * For example:
   * {{{
   *   FROM db.tbl1 A
   *   INSERT INTO dbo.tbl1 SELECT * WHERE A.value = 10 LIMIT 5
   *   INSERT INTO dbo.tbl2 SELECT * WHERE A.value = 12
   * }}}
   * This (Hive) feature cannot be combined with set-operators.
   */
  override def visitMultiInsertQuery(ctx: MultiInsertQueryContext): LogicalPlan = withOrigin(ctx) {
    val from = visitFromClause(ctx.fromClause)

    // Build the insert clauses.
    val inserts = ctx.multiInsertQueryBody.asScala.map { body =>
      withInsertInto(body.insertInto,
        withFromStatementBody(body.fromStatementBody, from).
          optionalMap(body.fromStatementBody.queryOrganization)(withQueryResultClauses))
    }

    // If there are multiple INSERTS just UNION them together into one query.
    if (inserts.length == 1) {
      inserts.head
    } else {
      Union(inserts)
    }
  }

  /**
   * Create a logical plan for a regular (single-insert) query.
   */
  override def visitSingleInsertQuery(
      ctx: SingleInsertQueryContext): LogicalPlan = withOrigin(ctx) {
    withInsertInto(
      ctx.insertInto(),
      plan(ctx.queryTerm).optionalMap(ctx.queryOrganization)(withQueryResultClauses))
  }

  /**
   * Parameters used for writing query to a table:
   *   (multipartIdentifier, partitionKeys, ifPartitionNotExists).
   */
  type InsertTableParams = (Seq[String], Map[String, Option[String]], Boolean)

  /**
   * Parameters used for writing query to a directory: (isLocal, CatalogStorageFormat, provider).
   */
  type InsertDirParams = (Boolean, CatalogStorageFormat, Option[String])

  /**
   * Add an
   * {{{
   *   INSERT OVERWRITE TABLE tableIdentifier [partitionSpec [IF NOT EXISTS]]?
   *   INSERT INTO [TABLE] tableIdentifier [partitionSpec]
   *   INSERT OVERWRITE [LOCAL] DIRECTORY STRING [rowFormat] [createFileFormat]
   *   INSERT OVERWRITE [LOCAL] DIRECTORY [STRING] tableProvider [OPTIONS tablePropertyList]
   * }}}
   * operation to logical plan
   */
  private def withInsertInto(
      ctx: InsertIntoContext,
      query: LogicalPlan): LogicalPlan = withOrigin(ctx) {
    ctx match {
      case table: InsertIntoTableContext =>
        val (tableIdent, partition, ifPartitionNotExists) = visitInsertIntoTable(table)
        InsertIntoStatement(
          UnresolvedRelation(tableIdent),
          partition,
          query,
          overwrite = false,
          ifPartitionNotExists)
      case table: InsertOverwriteTableContext =>
        val (tableIdent, partition, ifPartitionNotExists) = visitInsertOverwriteTable(table)
        InsertIntoStatement(
          UnresolvedRelation(tableIdent),
          partition,
          query,
          overwrite = true,
          ifPartitionNotExists)
      case dir: InsertOverwriteDirContext =>
        val (isLocal, storage, provider) = visitInsertOverwriteDir(dir)
        InsertIntoDir(isLocal, storage, provider, query, overwrite = true)
      case hiveDir: InsertOverwriteHiveDirContext =>
        val (isLocal, storage, provider) = visitInsertOverwriteHiveDir(hiveDir)
        InsertIntoDir(isLocal, storage, provider, query, overwrite = true)
      case _ =>
        throw new ParseException("Invalid InsertIntoContext", ctx)
    }
  }

  /**
   * Add an INSERT INTO TABLE operation to the logical plan.
   */
  override def visitInsertIntoTable(
      ctx: InsertIntoTableContext): InsertTableParams = withOrigin(ctx) {
    val tableIdent = visitMultipartIdentifier(ctx.multipartIdentifier)
    val partitionKeys = Option(ctx.partitionSpec).map(visitPartitionSpec).getOrElse(Map.empty)

    if (ctx.EXISTS != null) {
      operationNotAllowed("INSERT INTO ... IF NOT EXISTS", ctx)
    }

    (tableIdent, partitionKeys, false)
  }

  /**
   * Add an INSERT OVERWRITE TABLE operation to the logical plan.
   */
  override def visitInsertOverwriteTable(
      ctx: InsertOverwriteTableContext): InsertTableParams = withOrigin(ctx) {
    assert(ctx.OVERWRITE() != null)
    val tableIdent = visitMultipartIdentifier(ctx.multipartIdentifier)
    val partitionKeys = Option(ctx.partitionSpec).map(visitPartitionSpec).getOrElse(Map.empty)

    val dynamicPartitionKeys: Map[String, Option[String]] = partitionKeys.filter(_._2.isEmpty)
    if (ctx.EXISTS != null && dynamicPartitionKeys.nonEmpty) {
      operationNotAllowed("IF NOT EXISTS with dynamic partitions: " +
        dynamicPartitionKeys.keys.mkString(", "), ctx)
    }

    (tableIdent, partitionKeys, ctx.EXISTS() != null)
  }

  /**
   * Write to a directory, returning a [[InsertIntoDir]] logical plan.
   */
  override def visitInsertOverwriteDir(
      ctx: InsertOverwriteDirContext): InsertDirParams = withOrigin(ctx) {
    throw new ParseException("INSERT OVERWRITE DIRECTORY is not supported", ctx)
  }

  /**
   * Write to a directory, returning a [[InsertIntoDir]] logical plan.
   */
  override def visitInsertOverwriteHiveDir(
      ctx: InsertOverwriteHiveDirContext): InsertDirParams = withOrigin(ctx) {
    throw new ParseException("INSERT OVERWRITE DIRECTORY is not supported", ctx)
  }

  override def visitDeleteFromTable(
      ctx: DeleteFromTableContext): LogicalPlan = withOrigin(ctx) {

    val tableId = visitMultipartIdentifier(ctx.multipartIdentifier)
    val tableAlias = if (ctx.tableAlias() != null) {
      val ident = ctx.tableAlias().strictIdentifier()
      // We do not allow columns aliases after table alias.
      if (ctx.tableAlias().identifierList() != null) {
        throw new ParseException("Columns aliases is not allowed in DELETE.",
          ctx.tableAlias().identifierList())
      }
      if (ident != null) Some(ident.getText) else None
    } else {
      None
    }
    val predicate = if (ctx.whereClause() != null) {
      Some(expression(ctx.whereClause().booleanExpression()))
    } else {
      None
    }

    DeleteFromStatement(tableId, tableAlias, predicate)
  }

  override def visitUpdateTable(ctx: UpdateTableContext): LogicalPlan = withOrigin(ctx) {
    val tableId = visitMultipartIdentifier(ctx.multipartIdentifier)
    val tableAlias = if (ctx.tableAlias() != null) {
      val ident = ctx.tableAlias().strictIdentifier()
      // We do not allow columns aliases after table alias.
      if (ctx.tableAlias().identifierList() != null) {
        throw new ParseException("Columns aliases is not allowed in UPDATE.",
          ctx.tableAlias().identifierList())
      }
      if (ident != null) Some(ident.getText) else None
    } else {
      None
    }
    val (attrs, values) = ctx.setClause().assign().asScala.map {
      kv => visitMultipartIdentifier(kv.key) -> expression(kv.value)
    }.unzip
    val predicate = if (ctx.whereClause() != null) {
      Some(expression(ctx.whereClause().booleanExpression()))
    } else {
      None
    }

    UpdateTableStatement(
      tableId,
      tableAlias,
      attrs,
      values,
      predicate)
  }

  /**
   * Create a partition specification map.
   */
  override def visitPartitionSpec(
      ctx: PartitionSpecContext): Map[String, Option[String]] = withOrigin(ctx) {
    val parts = ctx.partitionVal.asScala.map { pVal =>
      val name = pVal.identifier.getText
      val value = Option(pVal.constant).map(visitStringConstant)
      name -> value
    }
    // Before calling `toMap`, we check duplicated keys to avoid silently ignore partition values
    // in partition spec like PARTITION(a='1', b='2', a='3'). The real semantical check for
    // partition columns will be done in analyzer.
    checkDuplicateKeys(parts, ctx)
    parts.toMap
  }

  /**
   * Create a partition specification map without optional values.
   */
  protected def visitNonOptionalPartitionSpec(
      ctx: PartitionSpecContext): Map[String, String] = withOrigin(ctx) {
    visitPartitionSpec(ctx).map {
      case (key, None) => throw new ParseException(s"Found an empty partition key '$key'.", ctx)
      case (key, Some(value)) => key -> value
    }
  }

  /**
   * Convert a constant of any type into a string. This is typically used in DDL commands, and its
   * main purpose is to prevent slight differences due to back to back conversions i.e.:
   * String -> Literal -> String.
   */
  protected def visitStringConstant(ctx: ConstantContext): String = withOrigin(ctx) {
    ctx match {
      case s: StringLiteralContext => createString(s)
      case o => o.getText
    }
  }

  /**
   * Add ORDER BY/SORT BY/CLUSTER BY/DISTRIBUTE BY/LIMIT/WINDOWS clauses to the logical plan. These
   * clauses determine the shape (ordering/partitioning/rows) of the query result.
   */
  private def withQueryResultClauses(
      ctx: QueryOrganizationContext,
      query: LogicalPlan): LogicalPlan = withOrigin(ctx) {
    import ctx._

    // Handle ORDER BY, SORT BY, DISTRIBUTE BY, and CLUSTER BY clause.
    val withOrder = if (
      !order.isEmpty && sort.isEmpty && distributeBy.isEmpty && clusterBy.isEmpty) {
      // ORDER BY ...
      Sort(order.asScala.map(visitSortItem), global = true, query)
    } else if (order.isEmpty && !sort.isEmpty && distributeBy.isEmpty && clusterBy.isEmpty) {
      // SORT BY ...
      Sort(sort.asScala.map(visitSortItem), global = false, query)
    } else if (order.isEmpty && sort.isEmpty && !distributeBy.isEmpty && clusterBy.isEmpty) {
      // DISTRIBUTE BY ...
      withRepartitionByExpression(ctx, expressionList(distributeBy), query)
    } else if (order.isEmpty && !sort.isEmpty && !distributeBy.isEmpty && clusterBy.isEmpty) {
      // SORT BY ... DISTRIBUTE BY ...
      Sort(
        sort.asScala.map(visitSortItem),
        global = false,
        withRepartitionByExpression(ctx, expressionList(distributeBy), query))
    } else if (order.isEmpty && sort.isEmpty && distributeBy.isEmpty && !clusterBy.isEmpty) {
      // CLUSTER BY ...
      val expressions = expressionList(clusterBy)
      Sort(
        expressions.map(SortOrder(_, Ascending)),
        global = false,
        withRepartitionByExpression(ctx, expressions, query))
    } else if (order.isEmpty && sort.isEmpty && distributeBy.isEmpty && clusterBy.isEmpty) {
      // [EMPTY]
      query
    } else {
      throw new ParseException(
        "Combination of ORDER BY/SORT BY/DISTRIBUTE BY/CLUSTER BY is not supported", ctx)
    }

    // WINDOWS
    val withWindow = withOrder.optionalMap(windowClause)(withWindowClause)

    // LIMIT
    // - LIMIT ALL is the same as omitting the LIMIT clause
    withWindow.optional(limit) {
      Limit(typedVisit(limit), withWindow)
    }
  }

  /**
   * Create a clause for DISTRIBUTE BY.
   */
  protected def withRepartitionByExpression(
      ctx: QueryOrganizationContext,
      expressions: Seq[Expression],
      query: LogicalPlan): LogicalPlan = {
    throw new ParseException("DISTRIBUTE BY is not supported", ctx)
  }

  override def visitTransformQuerySpecification(
      ctx: TransformQuerySpecificationContext): LogicalPlan = withOrigin(ctx) {
    val from = OneRowRelation().optional(ctx.fromClause) {
      visitFromClause(ctx.fromClause)
    }
    withTransformQuerySpecification(ctx, ctx.transformClause, ctx.whereClause, from)
  }

  override def visitRegularQuerySpecification(
      ctx: RegularQuerySpecificationContext): LogicalPlan = withOrigin(ctx) {
    val from = OneRowRelation().optional(ctx.fromClause) {
      visitFromClause(ctx.fromClause)
    }
    withSelectQuerySpecification(
      ctx,
      ctx.selectClause,
      ctx.lateralView,
      ctx.whereClause,
      ctx.aggregationClause,
      ctx.havingClause,
      ctx.windowClause,
      from
    )
  }

  override def visitNamedExpressionSeq(
      ctx: NamedExpressionSeqContext): Seq[Expression] = {
    Option(ctx).toSeq
      .flatMap(_.namedExpression.asScala)
      .map(typedVisit[Expression])
  }

  /**
   * Create a logical plan using a having clause.
   */
  private def withHavingClause(
      ctx: HavingClauseContext, plan: LogicalPlan): LogicalPlan = {
    // Note that we add a cast to non-predicate expressions. If the expression itself is
    // already boolean, the optimizer will get rid of the unnecessary cast.
    val predicate = expression(ctx.booleanExpression) match {
      case p: Predicate => p
      case e => Cast(e, BooleanType)
    }
    Filter(predicate, plan)
  }

  /**
   * Create a logical plan using a where clause.
   */
  private def withWhereClause(ctx: WhereClauseContext, plan: LogicalPlan): LogicalPlan = {
    Filter(expression(ctx.booleanExpression), plan)
  }

  /**
   * Add a hive-style transform (SELECT TRANSFORM/MAP/REDUCE) query specification to a logical plan.
   */
  private def withTransformQuerySpecification(
      ctx: ParserRuleContext,
      transformClause: TransformClauseContext,
      whereClause: WhereClauseContext,
    relation: LogicalPlan): LogicalPlan = withOrigin(ctx) {
    // Add where.
    val withFilter = relation.optionalMap(whereClause)(withWhereClause)

    // Create the transform.
    val expressions = visitNamedExpressionSeq(transformClause.namedExpressionSeq)

    // Create the attributes.
    val (attributes, schemaLess) = if (transformClause.colTypeList != null) {
      // Typed return columns.
      (createSchema(transformClause.colTypeList).toAttributes, false)
    } else if (transformClause.identifierSeq != null) {
      // Untyped return columns.
      val attrs = visitIdentifierSeq(transformClause.identifierSeq).map { name =>
        AttributeReference(name, StringType, nullable = true)()
      }
      (attrs, false)
    } else {
      (Seq(AttributeReference("key", StringType)(),
        AttributeReference("value", StringType)()), true)
    }

    // Create the transform.
    ScriptTransformation(
      expressions,
      string(transformClause.script),
      attributes,
      withFilter,
      withScriptIOSchema(
        ctx,
        transformClause.inRowFormat,
        transformClause.recordWriter,
        transformClause.outRowFormat,
        transformClause.recordReader,
        schemaLess
      )
    )
  }

  /**
   * Add a regular (SELECT) query specification to a logical plan. The query specification
   * is the core of the logical plan, this is where sourcing (FROM clause), projection (SELECT),
   * aggregation (GROUP BY ... HAVING ...) and filtering (WHERE) takes place.
   *
   * Note that query hints are ignored (both by the parser and the builder).
   */
  private def withSelectQuerySpecification(
      ctx: ParserRuleContext,
      selectClause: SelectClauseContext,
      lateralView: java.util.List[LateralViewContext],
      whereClause: WhereClauseContext,
      aggregationClause: AggregationClauseContext,
      havingClause: HavingClauseContext,
      windowClause: WindowClauseContext,
      relation: LogicalPlan): LogicalPlan = withOrigin(ctx) {
    // Add lateral views.
    val withLateralView = lateralView.asScala.foldLeft(relation)(withGenerate)

    // Add where.
    val withFilter = withLateralView.optionalMap(whereClause)(withWhereClause)

    val expressions = visitNamedExpressionSeq(selectClause.namedExpressionSeq)
    // Add aggregation or a project.
    val namedExpressions = expressions.map {
      case e: NamedExpression => e
      case e: Expression => UnresolvedAlias(e)
    }

    def createProject() = if (namedExpressions.nonEmpty) {
      Project(namedExpressions, withFilter)
    } else {
      withFilter
    }

    val withProject = if (aggregationClause == null && havingClause != null) {
      if (conf.getConf(SQLConf.LEGACY_HAVING_WITHOUT_GROUP_BY_AS_WHERE)) {
        // If the legacy conf is set, treat HAVING without GROUP BY as WHERE.
        withHavingClause(havingClause, createProject())
      } else {
        // According to SQL standard, HAVING without GROUP BY means global aggregate.
        withHavingClause(havingClause, Aggregate(Nil, namedExpressions, withFilter))
      }
    } else if (aggregationClause != null) {
      val aggregate = withAggregationClause(aggregationClause, namedExpressions, withFilter)
      aggregate.optionalMap(havingClause)(withHavingClause)
    } else {
      // When hitting this branch, `having` must be null.
      createProject()
    }

    // Distinct
    val withDistinct = if (
      selectClause.setQuantifier() != null &&
      selectClause.setQuantifier().DISTINCT() != null) {
      Distinct(withProject)
    } else {
      withProject
    }

    // Window
    val withWindow = withDistinct.optionalMap(windowClause)(withWindowClause)

    // Hint
    selectClause.hints.asScala.foldRight(withWindow)(withHints)
  }

  /**
   * Create a (Hive based) [[ScriptInputOutputSchema]].
   */
  protected def withScriptIOSchema(
      ctx: ParserRuleContext,
      inRowFormat: RowFormatContext,
      recordWriter: Token,
      outRowFormat: RowFormatContext,
      recordReader: Token,
      schemaLess: Boolean): ScriptInputOutputSchema = {
    throw new ParseException("Script Transform is not supported", ctx)
  }

  /**
   * Create a logical plan for a given 'FROM' clause. Note that we support multiple (comma
   * separated) relations here, these get converted into a single plan by condition-less inner join.
   */
  override def visitFromClause(ctx: FromClauseContext): LogicalPlan = withOrigin(ctx) {
    val from = ctx.relation.asScala.foldLeft(null: LogicalPlan) { (left, relation) =>
      val right = plan(relation.relationPrimary)
      val join = right.optionalMap(left)(Join(_, _, Inner, None, JoinHint.NONE))
      withJoinRelations(join, relation)
    }
    if (ctx.pivotClause() != null) {
      if (!ctx.lateralView.isEmpty) {
        throw new ParseException("LATERAL cannot be used together with PIVOT in FROM clause", ctx)
      }
      withPivot(ctx.pivotClause, from)
    } else {
      ctx.lateralView.asScala.foldLeft(from)(withGenerate)
    }
  }

  /**
   * Connect two queries by a Set operator.
   *
   * Supported Set operators are:
   * - UNION [ DISTINCT | ALL ]
   * - EXCEPT [ DISTINCT | ALL ]
   * - MINUS [ DISTINCT | ALL ]
   * - INTERSECT [DISTINCT | ALL]
   */
  override def visitSetOperation(ctx: SetOperationContext): LogicalPlan = withOrigin(ctx) {
    val left = plan(ctx.left)
    val right = plan(ctx.right)
    val all = Option(ctx.setQuantifier()).exists(_.ALL != null)
    ctx.operator.getType match {
      case SqlBaseParser.UNION if all =>
        Union(left, right)
      case SqlBaseParser.UNION =>
        Distinct(Union(left, right))
      case SqlBaseParser.INTERSECT if all =>
        Intersect(left, right, isAll = true)
      case SqlBaseParser.INTERSECT =>
        Intersect(left, right, isAll = false)
      case SqlBaseParser.EXCEPT if all =>
        Except(left, right, isAll = true)
      case SqlBaseParser.EXCEPT =>
        Except(left, right, isAll = false)
      case SqlBaseParser.SETMINUS if all =>
        Except(left, right, isAll = true)
      case SqlBaseParser.SETMINUS =>
        Except(left, right, isAll = false)
    }
  }

  /**
   * Add a [[WithWindowDefinition]] operator to a logical plan.
   */
  private def withWindowClause(
      ctx: WindowClauseContext,
      query: LogicalPlan): LogicalPlan = withOrigin(ctx) {
    // Collect all window specifications defined in the WINDOW clause.
    val baseWindowMap = ctx.namedWindow.asScala.map {
      wCtx =>
        (wCtx.name.getText, typedVisit[WindowSpec](wCtx.windowSpec))
    }.toMap

    // Handle cases like
    // window w1 as (partition by p_mfgr order by p_name
    //               range between 2 preceding and 2 following),
    //        w2 as w1
    val windowMapView = baseWindowMap.mapValues {
      case WindowSpecReference(name) =>
        baseWindowMap.get(name) match {
          case Some(spec: WindowSpecDefinition) =>
            spec
          case Some(ref) =>
            throw new ParseException(s"Window reference '$name' is not a window specification", ctx)
          case None =>
            throw new ParseException(s"Cannot resolve window reference '$name'", ctx)
        }
      case spec: WindowSpecDefinition => spec
    }

    // Note that mapValues creates a view instead of materialized map. We force materialization by
    // mapping over identity.
    WithWindowDefinition(windowMapView.map(identity), query)
  }

  /**
   * Add an [[Aggregate]] or [[GroupingSets]] to a logical plan.
   */
  private def withAggregationClause(
      ctx: AggregationClauseContext,
      selectExpressions: Seq[NamedExpression],
      query: LogicalPlan): LogicalPlan = withOrigin(ctx) {
    val groupByExpressions = expressionList(ctx.groupingExpressions)

    if (ctx.GROUPING != null) {
      // GROUP BY .... GROUPING SETS (...)
      val selectedGroupByExprs =
        ctx.groupingSet.asScala.map(_.expression.asScala.map(e => expression(e)))
      GroupingSets(selectedGroupByExprs, groupByExpressions, query, selectExpressions)
    } else {
      // GROUP BY .... (WITH CUBE | WITH ROLLUP)?
      val mappedGroupByExpressions = if (ctx.CUBE != null) {
        Seq(Cube(groupByExpressions))
      } else if (ctx.ROLLUP != null) {
        Seq(Rollup(groupByExpressions))
      } else {
        groupByExpressions
      }
      Aggregate(mappedGroupByExpressions, selectExpressions, query)
    }
  }

  /**
   * Add [[UnresolvedHint]]s to a logical plan.
   */
  private def withHints(
      ctx: HintContext,
      query: LogicalPlan): LogicalPlan = withOrigin(ctx) {
    var plan = query
    ctx.hintStatements.asScala.reverse.foreach { case stmt =>
      plan = UnresolvedHint(stmt.hintName.getText, stmt.parameters.asScala.map(expression), plan)
    }
    plan
  }

  /**
   * Add a [[Pivot]] to a logical plan.
   */
  private def withPivot(
      ctx: PivotClauseContext,
      query: LogicalPlan): LogicalPlan = withOrigin(ctx) {
    val aggregates = Option(ctx.aggregates).toSeq
      .flatMap(_.namedExpression.asScala)
      .map(typedVisit[Expression])
    val pivotColumn = if (ctx.pivotColumn.identifiers.size == 1) {
      UnresolvedAttribute.quoted(ctx.pivotColumn.identifier.getText)
    } else {
      CreateStruct(
        ctx.pivotColumn.identifiers.asScala.map(
          identifier => UnresolvedAttribute.quoted(identifier.getText)))
    }
    val pivotValues = ctx.pivotValues.asScala.map(visitPivotValue)
    Pivot(None, pivotColumn, pivotValues, aggregates, query)
  }

  /**
   * Create a Pivot column value with or without an alias.
   */
  override def visitPivotValue(ctx: PivotValueContext): Expression = withOrigin(ctx) {
    val e = expression(ctx.expression)
    if (ctx.identifier != null) {
      Alias(e, ctx.identifier.getText)()
    } else {
      e
    }
  }

  /**
   * Add a [[Generate]] (Lateral View) to a logical plan.
   */
  private def withGenerate(
      query: LogicalPlan,
      ctx: LateralViewContext): LogicalPlan = withOrigin(ctx) {
    val expressions = expressionList(ctx.expression)
    Generate(
      UnresolvedGenerator(visitFunctionName(ctx.qualifiedName), expressions),
      unrequiredChildIndex = Nil,
      outer = ctx.OUTER != null,
      // scalastyle:off caselocale
      Some(ctx.tblName.getText.toLowerCase),
      // scalastyle:on caselocale
      ctx.colName.asScala.map(_.getText).map(UnresolvedAttribute.apply),
      query)
  }

  /**
   * Create a single relation referenced in a FROM clause. This method is used when a part of the
   * join condition is nested, for example:
   * {{{
   *   select * from t1 join (t2 cross join t3) on col1 = col2
   * }}}
   */
  override def visitRelation(ctx: RelationContext): LogicalPlan = withOrigin(ctx) {
    withJoinRelations(plan(ctx.relationPrimary), ctx)
  }

  /**
   * Join one more [[LogicalPlan]]s to the current logical plan.
   */
  private def withJoinRelations(base: LogicalPlan, ctx: RelationContext): LogicalPlan = {
    ctx.joinRelation.asScala.foldLeft(base) { (left, join) =>
      withOrigin(join) {
        val baseJoinType = join.joinType match {
          case null => Inner
          case jt if jt.CROSS != null => Cross
          case jt if jt.FULL != null => FullOuter
          case jt if jt.SEMI != null => LeftSemi
          case jt if jt.ANTI != null => LeftAnti
          case jt if jt.LEFT != null => LeftOuter
          case jt if jt.RIGHT != null => RightOuter
          case _ => Inner
        }

        // Resolve the join type and join condition
        val (joinType, condition) = Option(join.joinCriteria) match {
          case Some(c) if c.USING != null =>
            (UsingJoin(baseJoinType, visitIdentifierList(c.identifierList)), None)
          case Some(c) if c.booleanExpression != null =>
            (baseJoinType, Option(expression(c.booleanExpression)))
          case None if join.NATURAL != null =>
            if (baseJoinType == Cross) {
              throw new ParseException("NATURAL CROSS JOIN is not supported", ctx)
            }
            (NaturalJoin(baseJoinType), None)
          case None =>
            (baseJoinType, None)
        }
        Join(left, plan(join.right), joinType, condition, JoinHint.NONE)
      }
    }
  }

  /**
   * Add a [[Sample]] to a logical plan.
   *
   * This currently supports the following sampling methods:
   * - TABLESAMPLE(x ROWS): Sample the table down to the given number of rows.
   * - TABLESAMPLE(x PERCENT): Sample the table down to the given percentage. Note that percentages
   * are defined as a number between 0 and 100.
   * - TABLESAMPLE(BUCKET x OUT OF y): Sample the table down to a 'x' divided by 'y' fraction.
   */
  private def withSample(ctx: SampleContext, query: LogicalPlan): LogicalPlan = withOrigin(ctx) {
    // Create a sampled plan if we need one.
    def sample(fraction: Double): Sample = {
      // The range of fraction accepted by Sample is [0, 1]. Because Hive's block sampling
      // function takes X PERCENT as the input and the range of X is [0, 100], we need to
      // adjust the fraction.
      val eps = RandomSampler.roundingEpsilon
      validate(fraction >= 0.0 - eps && fraction <= 1.0 + eps,
        s"Sampling fraction ($fraction) must be on interval [0, 1]",
        ctx)
      Sample(0.0, fraction, withReplacement = false, (math.random * 1000).toInt, query)
    }

    if (ctx.sampleMethod() == null) {
      throw new ParseException("TABLESAMPLE does not accept empty inputs.", ctx)
    }

    ctx.sampleMethod() match {
      case ctx: SampleByRowsContext =>
        Limit(expression(ctx.expression), query)

      case ctx: SampleByPercentileContext =>
        val fraction = ctx.percentage.getText.toDouble
        val sign = if (ctx.negativeSign == null) 1 else -1
        sample(sign * fraction / 100.0d)

      case ctx: SampleByBytesContext =>
        val bytesStr = ctx.bytes.getText
        if (bytesStr.matches("[0-9]+[bBkKmMgG]")) {
          throw new ParseException("TABLESAMPLE(byteLengthLiteral) is not supported", ctx)
        } else {
          throw new ParseException(
            bytesStr + " is not a valid byte length literal, " +
              "expected syntax: DIGIT+ ('B' | 'K' | 'M' | 'G')", ctx)
        }

      case ctx: SampleByBucketContext if ctx.ON() != null =>
        if (ctx.identifier != null) {
          throw new ParseException(
            "TABLESAMPLE(BUCKET x OUT OF y ON colname) is not supported", ctx)
        } else {
          throw new ParseException(
            "TABLESAMPLE(BUCKET x OUT OF y ON function) is not supported", ctx)
        }

      case ctx: SampleByBucketContext =>
        sample(ctx.numerator.getText.toDouble / ctx.denominator.getText.toDouble)
    }
  }

  /**
   * Create a logical plan for a sub-query.
   */
  override def visitSubquery(ctx: SubqueryContext): LogicalPlan = withOrigin(ctx) {
    plan(ctx.query)
  }

  /**
   * Create an un-aliased table reference. This is typically used for top-level table references,
   * for example:
   * {{{
   *   INSERT INTO db.tbl2
   *   TABLE db.tbl1
   * }}}
   */
  override def visitTable(ctx: TableContext): LogicalPlan = withOrigin(ctx) {
    UnresolvedRelation(visitMultipartIdentifier(ctx.multipartIdentifier))
  }

  /**
   * Create an aliased table reference. This is typically used in FROM clauses.
   */
  override def visitTableName(ctx: TableNameContext): LogicalPlan = withOrigin(ctx) {
    val tableId = visitMultipartIdentifier(ctx.multipartIdentifier)
    val table = mayApplyAliasPlan(ctx.tableAlias, UnresolvedRelation(tableId))
    table.optionalMap(ctx.sample)(withSample)
  }

  /**
   * Create a table-valued function call with arguments, e.g. range(1000)
   */
  override def visitTableValuedFunction(ctx: TableValuedFunctionContext)
      : LogicalPlan = withOrigin(ctx) {
    val func = ctx.functionTable
    val aliases = if (func.tableAlias.identifierList != null) {
      visitIdentifierList(func.tableAlias.identifierList)
    } else {
      Seq.empty
    }

    val tvf = UnresolvedTableValuedFunction(
      func.funcName.getText, func.expression.asScala.map(expression), aliases)
    tvf.optionalMap(func.tableAlias.strictIdentifier)(aliasPlan)
  }

  /**
   * Create an inline table (a virtual table in Hive parlance).
   */
  override def visitInlineTable(ctx: InlineTableContext): LogicalPlan = withOrigin(ctx) {
    // Get the backing expressions.
    val rows = ctx.expression.asScala.map { e =>
      expression(e) match {
        // inline table comes in two styles:
        // style 1: values (1), (2), (3)  -- multiple columns are supported
        // style 2: values 1, 2, 3  -- only a single column is supported here
        case struct: CreateNamedStruct => struct.valExprs // style 1
        case child => Seq(child)                          // style 2
      }
    }

    val aliases = if (ctx.tableAlias.identifierList != null) {
      visitIdentifierList(ctx.tableAlias.identifierList)
    } else {
      Seq.tabulate(rows.head.size)(i => s"col${i + 1}")
    }

    val table = UnresolvedInlineTable(aliases, rows)
    table.optionalMap(ctx.tableAlias.strictIdentifier)(aliasPlan)
  }

  /**
   * Create an alias (SubqueryAlias) for a join relation. This is practically the same as
   * visitAliasedQuery and visitNamedExpression, ANTLR4 however requires us to use 3 different
   * hooks. We could add alias names for output columns, for example:
   * {{{
   *   SELECT a, b, c, d FROM (src1 s1 INNER JOIN src2 s2 ON s1.id = s2.id) dst(a, b, c, d)
   * }}}
   */
  override def visitAliasedRelation(ctx: AliasedRelationContext): LogicalPlan = withOrigin(ctx) {
    val relation = plan(ctx.relation).optionalMap(ctx.sample)(withSample)
    mayApplyAliasPlan(ctx.tableAlias, relation)
  }

  /**
   * Create an alias (SubqueryAlias) for a sub-query. This is practically the same as
   * visitAliasedRelation and visitNamedExpression, ANTLR4 however requires us to use 3 different
   * hooks. We could add alias names for output columns, for example:
   * {{{
   *   SELECT col1, col2 FROM testData AS t(col1, col2)
   * }}}
   */
  override def visitAliasedQuery(ctx: AliasedQueryContext): LogicalPlan = withOrigin(ctx) {
    val relation = plan(ctx.query).optionalMap(ctx.sample)(withSample)
    if (ctx.tableAlias.strictIdentifier == null) {
      // For un-aliased subqueries, use a default alias name that is not likely to conflict with
      // normal subquery names, so that parent operators can only access the columns in subquery by
      // unqualified names. Users can still use this special qualifier to access columns if they
      // know it, but that's not recommended.
      SubqueryAlias("__auto_generated_subquery_name", relation)
    } else {
      mayApplyAliasPlan(ctx.tableAlias, relation)
    }
  }

  /**
   * Create an alias ([[SubqueryAlias]]) for a [[LogicalPlan]].
   */
  private def aliasPlan(alias: ParserRuleContext, plan: LogicalPlan): LogicalPlan = {
    SubqueryAlias(alias.getText, plan)
  }

  /**
   * If aliases specified in a FROM clause, create a subquery alias ([[SubqueryAlias]]) and
   * column aliases for a [[LogicalPlan]].
   */
  private def mayApplyAliasPlan(tableAlias: TableAliasContext, plan: LogicalPlan): LogicalPlan = {
    if (tableAlias.strictIdentifier != null) {
      val subquery = SubqueryAlias(tableAlias.strictIdentifier.getText, plan)
      if (tableAlias.identifierList != null) {
        val columnNames = visitIdentifierList(tableAlias.identifierList)
        UnresolvedSubqueryColumnAliases(columnNames, subquery)
      } else {
        subquery
      }
    } else {
      plan
    }
  }

  /**
   * Create a Sequence of Strings for a parenthesis enclosed alias list.
   */
  override def visitIdentifierList(ctx: IdentifierListContext): Seq[String] = withOrigin(ctx) {
    visitIdentifierSeq(ctx.identifierSeq)
  }

  /**
   * Create a Sequence of Strings for an identifier list.
   */
  override def visitIdentifierSeq(ctx: IdentifierSeqContext): Seq[String] = withOrigin(ctx) {
    ctx.ident.asScala.map(_.getText)
  }

  /* ********************************************************************************************
   * Table Identifier parsing
   * ******************************************************************************************** */
  /**
   * Create a [[TableIdentifier]] from a 'tableName' or 'databaseName'.'tableName' pattern.
   */
  override def visitTableIdentifier(
      ctx: TableIdentifierContext): TableIdentifier = withOrigin(ctx) {
    TableIdentifier(ctx.table.getText, Option(ctx.db).map(_.getText))
  }

  /**
   * Create a [[FunctionIdentifier]] from a 'functionName' or 'databaseName'.'functionName' pattern.
   */
  override def visitFunctionIdentifier(
      ctx: FunctionIdentifierContext): FunctionIdentifier = withOrigin(ctx) {
    FunctionIdentifier(ctx.function.getText, Option(ctx.db).map(_.getText))
  }

  /**
   * Create a multi-part identifier.
   */
  override def visitMultipartIdentifier(
      ctx: MultipartIdentifierContext): Seq[String] = withOrigin(ctx) {
    ctx.parts.asScala.map(_.getText)
  }

  /* ********************************************************************************************
   * Expression parsing
   * ******************************************************************************************** */
  /**
   * Create an expression from the given context. This method just passes the context on to the
   * visitor and only takes care of typing (We assume that the visitor returns an Expression here).
   */
  protected def expression(ctx: ParserRuleContext): Expression = typedVisit(ctx)

  /**
   * Create sequence of expressions from the given sequence of contexts.
   */
  private def expressionList(trees: java.util.List[ExpressionContext]): Seq[Expression] = {
    trees.asScala.map(expression)
  }

  /**
   * Create a star (i.e. all) expression; this selects all elements (in the specified object).
   * Both un-targeted (global) and targeted aliases are supported.
   */
  override def visitStar(ctx: StarContext): Expression = withOrigin(ctx) {
    UnresolvedStar(Option(ctx.qualifiedName()).map(_.identifier.asScala.map(_.getText)))
  }

  /**
   * Create an aliased expression if an alias is specified. Both single and multi-aliases are
   * supported.
   */
  override def visitNamedExpression(ctx: NamedExpressionContext): Expression = withOrigin(ctx) {
    val e = expression(ctx.expression)
    if (ctx.name != null) {
      Alias(e, ctx.name.getText)()
    } else if (ctx.identifierList != null) {
      MultiAlias(e, visitIdentifierList(ctx.identifierList))
    } else {
      e
    }
  }

  /**
   * Combine a number of boolean expressions into a balanced expression tree. These expressions are
   * either combined by a logical [[And]] or a logical [[Or]].
   *
   * A balanced binary tree is created because regular left recursive trees cause considerable
   * performance degradations and can cause stack overflows.
   */
  override def visitLogicalBinary(ctx: LogicalBinaryContext): Expression = withOrigin(ctx) {
    val expressionType = ctx.operator.getType
    val expressionCombiner = expressionType match {
      case SqlBaseParser.AND => And.apply _
      case SqlBaseParser.OR => Or.apply _
    }

    // Collect all similar left hand contexts.
    val contexts = ArrayBuffer(ctx.right)
    var current = ctx.left
    def collectContexts: Boolean = current match {
      case lbc: LogicalBinaryContext if lbc.operator.getType == expressionType =>
        contexts += lbc.right
        current = lbc.left
        true
      case _ =>
        contexts += current
        false
    }
    while (collectContexts) {
      // No body - all updates take place in the collectContexts.
    }

    // Reverse the contexts to have them in the same sequence as in the SQL statement & turn them
    // into expressions.
    val expressions = contexts.reverseMap(expression)

    // Create a balanced tree.
    def reduceToExpressionTree(low: Int, high: Int): Expression = high - low match {
      case 0 =>
        expressions(low)
      case 1 =>
        expressionCombiner(expressions(low), expressions(high))
      case x =>
        val mid = low + x / 2
        expressionCombiner(
          reduceToExpressionTree(low, mid),
          reduceToExpressionTree(mid + 1, high))
    }
    reduceToExpressionTree(0, expressions.size - 1)
  }

  /**
   * Invert a boolean expression.
   */
  override def visitLogicalNot(ctx: LogicalNotContext): Expression = withOrigin(ctx) {
    Not(expression(ctx.booleanExpression()))
  }

  /**
   * Create a filtering correlated sub-query (EXISTS).
   */
  override def visitExists(ctx: ExistsContext): Expression = {
    Exists(plan(ctx.query))
  }

  /**
   * Create a comparison expression. This compares two expressions. The following comparison
   * operators are supported:
   * - Equal: '=' or '=='
   * - Null-safe Equal: '<=>'
   * - Not Equal: '<>' or '!='
   * - Less than: '<'
   * - Less then or Equal: '<='
   * - Greater than: '>'
   * - Greater then or Equal: '>='
   */
  override def visitComparison(ctx: ComparisonContext): Expression = withOrigin(ctx) {
    val left = expression(ctx.left)
    val right = expression(ctx.right)
    val operator = ctx.comparisonOperator().getChild(0).asInstanceOf[TerminalNode]
    operator.getSymbol.getType match {
      case SqlBaseParser.EQ =>
        EqualTo(left, right)
      case SqlBaseParser.NSEQ =>
        EqualNullSafe(left, right)
      case SqlBaseParser.NEQ | SqlBaseParser.NEQJ =>
        Not(EqualTo(left, right))
      case SqlBaseParser.LT =>
        LessThan(left, right)
      case SqlBaseParser.LTE =>
        LessThanOrEqual(left, right)
      case SqlBaseParser.GT =>
        GreaterThan(left, right)
      case SqlBaseParser.GTE =>
        GreaterThanOrEqual(left, right)
    }
  }

  /**
   * Create a predicated expression. A predicated expression is a normal expression with a
   * predicate attached to it, for example:
   * {{{
   *    a + 1 IS NULL
   * }}}
   */
  override def visitPredicated(ctx: PredicatedContext): Expression = withOrigin(ctx) {
    val e = expression(ctx.valueExpression)
    if (ctx.predicate != null) {
      withPredicate(e, ctx.predicate)
    } else {
      e
    }
  }

  /**
   * Add a predicate to the given expression. Supported expressions are:
   * - (NOT) BETWEEN
   * - (NOT) IN
   * - (NOT) LIKE
   * - (NOT) RLIKE
   * - IS (NOT) NULL.
   * - IS (NOT) (TRUE | FALSE | UNKNOWN)
   * - IS (NOT) DISTINCT FROM
   */
  private def withPredicate(e: Expression, ctx: PredicateContext): Expression = withOrigin(ctx) {
    // Invert a predicate if it has a valid NOT clause.
    def invertIfNotDefined(e: Expression): Expression = ctx.NOT match {
      case null => e
      case not => Not(e)
    }

    def getValueExpressions(e: Expression): Seq[Expression] = e match {
      case c: CreateNamedStruct => c.valExprs
      case other => Seq(other)
    }

    // Create the predicate.
    ctx.kind.getType match {
      case SqlBaseParser.BETWEEN =>
        // BETWEEN is translated to lower <= e && e <= upper
        invertIfNotDefined(And(
          GreaterThanOrEqual(e, expression(ctx.lower)),
          LessThanOrEqual(e, expression(ctx.upper))))
      case SqlBaseParser.IN if ctx.query != null =>
        invertIfNotDefined(InSubquery(getValueExpressions(e), ListQuery(plan(ctx.query))))
      case SqlBaseParser.IN =>
        invertIfNotDefined(In(e, ctx.expression.asScala.map(expression)))
      case SqlBaseParser.LIKE =>
        invertIfNotDefined(Like(e, expression(ctx.pattern)))
      case SqlBaseParser.RLIKE =>
        invertIfNotDefined(RLike(e, expression(ctx.pattern)))
      case SqlBaseParser.NULL if ctx.NOT != null =>
        IsNotNull(e)
      case SqlBaseParser.NULL =>
        IsNull(e)
      case SqlBaseParser.TRUE => ctx.NOT match {
        case null => IsTrue(e)
        case _ => IsNotTrue(e)
      }
      case SqlBaseParser.FALSE => ctx.NOT match {
        case null => IsFalse(e)
        case _ => IsNotFalse(e)
      }
      case SqlBaseParser.UNKNOWN => ctx.NOT match {
        case null => IsUnknown(e)
        case _ => IsNotUnknown(e)
      }
      case SqlBaseParser.DISTINCT if ctx.NOT != null =>
        EqualNullSafe(e, expression(ctx.right))
      case SqlBaseParser.DISTINCT =>
        Not(EqualNullSafe(e, expression(ctx.right)))
    }
  }

  /**
   * Create a binary arithmetic expression. The following arithmetic operators are supported:
   * - Multiplication: '*'
   * - Division: '/'
   * - Hive Long Division: 'DIV'
   * - Modulo: '%'
   * - Addition: '+'
   * - Subtraction: '-'
   * - Binary AND: '&'
   * - Binary XOR
   * - Binary OR: '|'
   */
  override def visitArithmeticBinary(ctx: ArithmeticBinaryContext): Expression = withOrigin(ctx) {
    val left = expression(ctx.left)
    val right = expression(ctx.right)
    ctx.operator.getType match {
      case SqlBaseParser.ASTERISK =>
        Multiply(left, right)
      case SqlBaseParser.SLASH =>
        Divide(left, right)
      case SqlBaseParser.PERCENT =>
        Remainder(left, right)
      case SqlBaseParser.DIV =>
        IntegralDivide(left, right)
      case SqlBaseParser.PLUS =>
        Add(left, right)
      case SqlBaseParser.MINUS =>
        Subtract(left, right)
      case SqlBaseParser.CONCAT_PIPE =>
        Concat(left :: right :: Nil)
      case SqlBaseParser.AMPERSAND =>
        BitwiseAnd(left, right)
      case SqlBaseParser.HAT =>
        BitwiseXor(left, right)
      case SqlBaseParser.PIPE =>
        BitwiseOr(left, right)
    }
  }

  /**
   * Create a unary arithmetic expression. The following arithmetic operators are supported:
   * - Plus: '+'
   * - Minus: '-'
   * - Bitwise Not: '~'
   */
  override def visitArithmeticUnary(ctx: ArithmeticUnaryContext): Expression = withOrigin(ctx) {
    val value = expression(ctx.valueExpression)
    ctx.operator.getType match {
      case SqlBaseParser.PLUS =>
        value
      case SqlBaseParser.MINUS =>
        UnaryMinus(value)
      case SqlBaseParser.TILDE =>
        BitwiseNot(value)
    }
  }

  override def visitCurrentDatetime(ctx: CurrentDatetimeContext): Expression = withOrigin(ctx) {
    if (conf.ansiEnabled) {
      ctx.name.getType match {
        case SqlBaseParser.CURRENT_DATE =>
          CurrentDate()
        case SqlBaseParser.CURRENT_TIMESTAMP =>
          CurrentTimestamp()
      }
    } else {
      // If the parser is not in ansi mode, we should return `UnresolvedAttribute`, in case there
      // are columns named `CURRENT_DATE` or `CURRENT_TIMESTAMP`.
      UnresolvedAttribute.quoted(ctx.name.getText)
    }
  }

  /**
   * Create a [[Cast]] expression.
   */
  override def visitCast(ctx: CastContext): Expression = withOrigin(ctx) {
    Cast(expression(ctx.expression), visitSparkDataType(ctx.dataType))
  }

  /**
   * Create a [[CreateStruct]] expression.
   */
  override def visitStruct(ctx: StructContext): Expression = withOrigin(ctx) {
    CreateStruct(ctx.argument.asScala.map(expression))
  }

  /**
   * Create a [[First]] expression.
   */
  override def visitFirst(ctx: FirstContext): Expression = withOrigin(ctx) {
    val ignoreNullsExpr = ctx.IGNORE != null
    First(expression(ctx.expression), Literal(ignoreNullsExpr)).toAggregateExpression()
  }

  /**
   * Create a [[Last]] expression.
   */
  override def visitLast(ctx: LastContext): Expression = withOrigin(ctx) {
    val ignoreNullsExpr = ctx.IGNORE != null
    Last(expression(ctx.expression), Literal(ignoreNullsExpr)).toAggregateExpression()
  }

  /**
   * Create a Position expression.
   */
  override def visitPosition(ctx: PositionContext): Expression = withOrigin(ctx) {
    new StringLocate(expression(ctx.substr), expression(ctx.str))
  }

  /**
   * Create a Extract expression.
   */
  override def visitExtract(ctx: ExtractContext): Expression = withOrigin(ctx) {
    val fieldStr = ctx.field.getText
    val source = expression(ctx.source)
    val extractField = DatePart.parseExtractField(fieldStr, source, {
      throw new ParseException(s"Literals of type '$fieldStr' are currently not supported.", ctx)
    })
    new DatePart(Literal(fieldStr), expression(ctx.source), extractField)
  }

  /**
   * Create a Substring/Substr expression.
   */
  override def visitSubstring(ctx: SubstringContext): Expression = withOrigin(ctx) {
    if (ctx.len != null) {
      Substring(expression(ctx.str), expression(ctx.pos), expression(ctx.len))
    } else {
      new Substring(expression(ctx.str), expression(ctx.pos))
    }
  }

  /**
   * Create a Trim expression.
   */
  override def visitTrim(ctx: TrimContext): Expression = withOrigin(ctx) {
    val srcStr = expression(ctx.srcStr)
    val trimStr = Option(ctx.trimStr).map(expression)
    Option(ctx.trimOption).map(_.getType).getOrElse(SqlBaseParser.BOTH) match {
      case SqlBaseParser.BOTH =>
        StringTrim(srcStr, trimStr)
      case SqlBaseParser.LEADING =>
        StringTrimLeft(srcStr, trimStr)
      case SqlBaseParser.TRAILING =>
        StringTrimRight(srcStr, trimStr)
      case other =>
        throw new ParseException("Function trim doesn't support with " +
          s"type $other. Please use BOTH, LEADING or TRAILING as trim type", ctx)
    }
  }

  /**
   * Create a Overlay expression.
   */
  override def visitOverlay(ctx: OverlayContext): Expression = withOrigin(ctx) {
    val input = expression(ctx.input)
    val replace = expression(ctx.replace)
    val position = expression(ctx.position)
    val lengthOpt = Option(ctx.length).map(expression)
    lengthOpt match {
      case Some(length) => Overlay(input, replace, position, length)
      case None => new Overlay(input, replace, position)
    }
  }

  /**
   * Create a (windowed) Function expression.
   */
  override def visitFunctionCall(ctx: FunctionCallContext): Expression = withOrigin(ctx) {
    // Create the function call.
    val name = ctx.qualifiedName.getText
    val isDistinct = Option(ctx.setQuantifier()).exists(_.DISTINCT != null)
    val arguments = ctx.argument.asScala.map(expression) match {
      case Seq(UnresolvedStar(None))
        if name.toLowerCase(Locale.ROOT) == "count" && !isDistinct =>
        // Transform COUNT(*) into COUNT(1).
        Seq(Literal(1))
      case expressions =>
        expressions
    }
    val function = UnresolvedFunction(visitFunctionName(ctx.qualifiedName), arguments, isDistinct)

    // Check if the function is evaluated in a windowed context.
    ctx.windowSpec match {
      case spec: WindowRefContext =>
        UnresolvedWindowExpression(function, visitWindowRef(spec))
      case spec: WindowDefContext =>
        WindowExpression(function, visitWindowDef(spec))
      case _ => function
    }
  }

  /**
   * Create a function database (optional) and name pair.
   */
  protected def visitFunctionName(ctx: QualifiedNameContext): FunctionIdentifier = {
    ctx.identifier().asScala.map(_.getText) match {
      case Seq(db, fn) => FunctionIdentifier(fn, Option(db))
      case Seq(fn) => FunctionIdentifier(fn, None)
      case other => throw new ParseException(s"Unsupported function name '${ctx.getText}'", ctx)
    }
  }

  /**
   * Create an [[LambdaFunction]].
   */
  override def visitLambda(ctx: LambdaContext): Expression = withOrigin(ctx) {
    val arguments = ctx.IDENTIFIER().asScala.map { name =>
      UnresolvedNamedLambdaVariable(UnresolvedAttribute.quoted(name.getText).nameParts)
    }
    val function = expression(ctx.expression).transformUp {
      case a: UnresolvedAttribute => UnresolvedNamedLambdaVariable(a.nameParts)
    }
    LambdaFunction(function, arguments)
  }

  /**
   * Create a reference to a window frame, i.e. [[WindowSpecReference]].
   */
  override def visitWindowRef(ctx: WindowRefContext): WindowSpecReference = withOrigin(ctx) {
    WindowSpecReference(ctx.name.getText)
  }

  /**
   * Create a window definition, i.e. [[WindowSpecDefinition]].
   */
  override def visitWindowDef(ctx: WindowDefContext): WindowSpecDefinition = withOrigin(ctx) {
    // CLUSTER BY ... | PARTITION BY ... ORDER BY ...
    val partition = ctx.partition.asScala.map(expression)
    val order = ctx.sortItem.asScala.map(visitSortItem)

    // RANGE/ROWS BETWEEN ...
    val frameSpecOption = Option(ctx.windowFrame).map { frame =>
      val frameType = frame.frameType.getType match {
        case SqlBaseParser.RANGE => RangeFrame
        case SqlBaseParser.ROWS => RowFrame
      }

      SpecifiedWindowFrame(
        frameType,
        visitFrameBound(frame.start),
        Option(frame.end).map(visitFrameBound).getOrElse(CurrentRow))
    }

    WindowSpecDefinition(
      partition,
      order,
      frameSpecOption.getOrElse(UnspecifiedFrame))
  }

  /**
   * Create or resolve a frame boundary expressions.
   */
  override def visitFrameBound(ctx: FrameBoundContext): Expression = withOrigin(ctx) {
    def value: Expression = {
      val e = expression(ctx.expression)
      validate(e.resolved && e.foldable, "Frame bound value must be a literal.", ctx)
      e
    }

    ctx.boundType.getType match {
      case SqlBaseParser.PRECEDING if ctx.UNBOUNDED != null =>
        UnboundedPreceding
      case SqlBaseParser.PRECEDING =>
        UnaryMinus(value)
      case SqlBaseParser.CURRENT =>
        CurrentRow
      case SqlBaseParser.FOLLOWING if ctx.UNBOUNDED != null =>
        UnboundedFollowing
      case SqlBaseParser.FOLLOWING =>
        value
    }
  }

  /**
   * Create a [[CreateStruct]] expression.
   */
  override def visitRowConstructor(ctx: RowConstructorContext): Expression = withOrigin(ctx) {
    CreateStruct(ctx.namedExpression().asScala.map(expression))
  }

  /**
   * Create a [[ScalarSubquery]] expression.
   */
  override def visitSubqueryExpression(
      ctx: SubqueryExpressionContext): Expression = withOrigin(ctx) {
    ScalarSubquery(plan(ctx.query))
  }

  /**
   * Create a value based [[CaseWhen]] expression. This has the following SQL form:
   * {{{
   *   CASE [expression]
   *    WHEN [value] THEN [expression]
   *    ...
   *    ELSE [expression]
   *   END
   * }}}
   */
  override def visitSimpleCase(ctx: SimpleCaseContext): Expression = withOrigin(ctx) {
    val e = expression(ctx.value)
    val branches = ctx.whenClause.asScala.map { wCtx =>
      (EqualTo(e, expression(wCtx.condition)), expression(wCtx.result))
    }
    CaseWhen(branches, Option(ctx.elseExpression).map(expression))
  }

  /**
   * Create a condition based [[CaseWhen]] expression. This has the following SQL syntax:
   * {{{
   *   CASE
   *    WHEN [predicate] THEN [expression]
   *    ...
   *    ELSE [expression]
   *   END
   * }}}
   *
   * @param ctx the parse tree
   *    */
  override def visitSearchedCase(ctx: SearchedCaseContext): Expression = withOrigin(ctx) {
    val branches = ctx.whenClause.asScala.map { wCtx =>
      (expression(wCtx.condition), expression(wCtx.result))
    }
    CaseWhen(branches, Option(ctx.elseExpression).map(expression))
  }

  /**
   * Currently only regex in expressions of SELECT statements are supported; in other
   * places, e.g., where `(a)?+.+` = 2, regex are not meaningful.
   */
  private def canApplyRegex(ctx: ParserRuleContext): Boolean = withOrigin(ctx) {
    var parent = ctx.getParent
    while (parent != null) {
      if (parent.isInstanceOf[NamedExpressionContext]) return true
      parent = parent.getParent
    }
    return false
  }

  /**
   * Create a dereference expression. The return type depends on the type of the parent.
   * If the parent is an [[UnresolvedAttribute]], it can be a [[UnresolvedAttribute]] or
   * a [[UnresolvedRegex]] for regex quoted in ``; if the parent is some other expression,
   * it can be [[UnresolvedExtractValue]].
   */
  override def visitDereference(ctx: DereferenceContext): Expression = withOrigin(ctx) {
    val attr = ctx.fieldName.getText
    expression(ctx.base) match {
      case unresolved_attr @ UnresolvedAttribute(nameParts) =>
        ctx.fieldName.getStart.getText match {
          case escapedIdentifier(columnNameRegex)
            if conf.supportQuotedRegexColumnName && canApplyRegex(ctx) =>
            UnresolvedRegex(columnNameRegex, Some(unresolved_attr.name),
              conf.caseSensitiveAnalysis)
          case _ =>
            UnresolvedAttribute(nameParts :+ attr)
        }
      case e =>
        UnresolvedExtractValue(e, Literal(attr))
    }
  }

  /**
   * Create an [[UnresolvedAttribute]] expression or a [[UnresolvedRegex]] if it is a regex
   * quoted in ``
   */
  override def visitColumnReference(ctx: ColumnReferenceContext): Expression = withOrigin(ctx) {
    ctx.getStart.getText match {
      case escapedIdentifier(columnNameRegex)
        if conf.supportQuotedRegexColumnName && canApplyRegex(ctx) =>
        UnresolvedRegex(columnNameRegex, None, conf.caseSensitiveAnalysis)
      case _ =>
        UnresolvedAttribute.quoted(ctx.getText)
    }

  }

  /**
   * Create an [[UnresolvedExtractValue]] expression, this is used for subscript access to an array.
   */
  override def visitSubscript(ctx: SubscriptContext): Expression = withOrigin(ctx) {
    UnresolvedExtractValue(expression(ctx.value), expression(ctx.index))
  }

  /**
   * Create an expression for an expression between parentheses. This is need because the ANTLR
   * visitor cannot automatically convert the nested context into an expression.
   */
  override def visitParenthesizedExpression(
     ctx: ParenthesizedExpressionContext): Expression = withOrigin(ctx) {
    expression(ctx.expression)
  }

  /**
   * Create a [[SortOrder]] expression.
   */
  override def visitSortItem(ctx: SortItemContext): SortOrder = withOrigin(ctx) {
    val direction = if (ctx.DESC != null) {
      Descending
    } else {
      Ascending
    }
    val nullOrdering = if (ctx.FIRST != null) {
      NullsFirst
    } else if (ctx.LAST != null) {
      NullsLast
    } else {
      direction.defaultNullOrdering
    }
    SortOrder(expression(ctx.expression), direction, nullOrdering, Set.empty)
  }

  /**
   * Create a typed Literal expression. A typed literal has the following SQL syntax:
   * {{{
   *   [TYPE] '[VALUE]'
   * }}}
   * Currently Date, Timestamp, Interval and Binary typed literals are supported.
   */
  override def visitTypeConstructor(ctx: TypeConstructorContext): Literal = withOrigin(ctx) {
    val value = string(ctx.STRING)
    val valueType = ctx.identifier.getText.toUpperCase(Locale.ROOT)
    def toLiteral[T](f: UTF8String => Option[T], t: DataType): Literal = {
      f(UTF8String.fromString(value)).map(Literal(_, t)).getOrElse {
        throw new ParseException(s"Cannot parse the $valueType value: $value", ctx)
      }
    }
    try {
      valueType match {
        case "DATE" =>
          toLiteral(stringToDate(_, getZoneId(SQLConf.get.sessionLocalTimeZone)), DateType)
        case "TIMESTAMP" =>
          val zoneId = getZoneId(SQLConf.get.sessionLocalTimeZone)
          toLiteral(stringToTimestamp(_, zoneId), TimestampType)
        case "INTERVAL" =>
          Literal(CalendarInterval.fromString(value), CalendarIntervalType)
        case "X" =>
          val padding = if (value.length % 2 != 0) "0" else ""
          Literal(DatatypeConverter.parseHexBinary(padding + value))
        case other =>
          throw new ParseException(s"Literals of type '$other' are currently not supported.", ctx)
      }
    } catch {
      case e: IllegalArgumentException =>
        val message = Option(e.getMessage).getOrElse(s"Exception parsing $valueType")
        throw new ParseException(message, ctx)
    }
  }

  /**
   * Create a NULL literal expression.
   */
  override def visitNullLiteral(ctx: NullLiteralContext): Literal = withOrigin(ctx) {
    Literal(null)
  }

  /**
   * Create a Boolean literal expression.
   */
  override def visitBooleanLiteral(ctx: BooleanLiteralContext): Literal = withOrigin(ctx) {
    if (ctx.getText.toBoolean) {
      Literal.TrueLiteral
    } else {
      Literal.FalseLiteral
    }
  }

  /**
   * Create an integral literal expression. The code selects the most narrow integral type
   * possible, either a BigDecimal, a Long or an Integer is returned.
   */
  override def visitIntegerLiteral(ctx: IntegerLiteralContext): Literal = withOrigin(ctx) {
    BigDecimal(ctx.getText) match {
      case v if v.isValidInt =>
        Literal(v.intValue())
      case v if v.isValidLong =>
        Literal(v.longValue())
      case v => Literal(v.underlying())
    }
  }

  /**
   * Create a decimal literal for a regular decimal number.
   */
  override def visitDecimalLiteral(ctx: DecimalLiteralContext): Literal = withOrigin(ctx) {
    Literal(BigDecimal(ctx.getText).underlying())
  }

  /** Create a numeric literal expression. */
  private def numericLiteral
      (ctx: NumberContext, minValue: BigDecimal, maxValue: BigDecimal, typeName: String)
      (converter: String => Any): Literal = withOrigin(ctx) {
    val rawStrippedQualifier = ctx.getText.substring(0, ctx.getText.length - 1)
    try {
      val rawBigDecimal = BigDecimal(rawStrippedQualifier)
      if (rawBigDecimal < minValue || rawBigDecimal > maxValue) {
        throw new ParseException(s"Numeric literal ${rawStrippedQualifier} does not " +
          s"fit in range [${minValue}, ${maxValue}] for type ${typeName}", ctx)
      }
      Literal(converter(rawStrippedQualifier))
    } catch {
      case e: NumberFormatException =>
        throw new ParseException(e.getMessage, ctx)
    }
  }

  /**
   * Create a Byte Literal expression.
   */
  override def visitTinyIntLiteral(ctx: TinyIntLiteralContext): Literal = {
    numericLiteral(ctx, Byte.MinValue, Byte.MaxValue, ByteType.simpleString)(_.toByte)
  }

  /**
   * Create a Short Literal expression.
   */
  override def visitSmallIntLiteral(ctx: SmallIntLiteralContext): Literal = {
    numericLiteral(ctx, Short.MinValue, Short.MaxValue, ShortType.simpleString)(_.toShort)
  }

  /**
   * Create a Long Literal expression.
   */
  override def visitBigIntLiteral(ctx: BigIntLiteralContext): Literal = {
    numericLiteral(ctx, Long.MinValue, Long.MaxValue, LongType.simpleString)(_.toLong)
  }

  /**
   * Create a Double Literal expression.
   */
  override def visitDoubleLiteral(ctx: DoubleLiteralContext): Literal = {
    numericLiteral(ctx, Double.MinValue, Double.MaxValue, DoubleType.simpleString)(_.toDouble)
  }

  /**
   * Create a BigDecimal Literal expression.
   */
  override def visitBigDecimalLiteral(ctx: BigDecimalLiteralContext): Literal = {
    val raw = ctx.getText.substring(0, ctx.getText.length - 2)
    try {
      Literal(BigDecimal(raw).underlying())
    } catch {
      case e: AnalysisException =>
        throw new ParseException(e.message, ctx)
    }
  }

  /**
   * Create a String literal expression.
   */
  override def visitStringLiteral(ctx: StringLiteralContext): Literal = withOrigin(ctx) {
    Literal(createString(ctx))
  }

  /**
   * Create a String from a string literal context. This supports multiple consecutive string
   * literals, these are concatenated, for example this expression "'hello' 'world'" will be
   * converted into "helloworld".
   *
   * Special characters can be escaped by using Hive/C-style escaping.
   */
  private def createString(ctx: StringLiteralContext): String = {
    if (conf.escapedStringLiterals) {
      ctx.STRING().asScala.map(stringWithoutUnescape).mkString
    } else {
      ctx.STRING().asScala.map(string).mkString
    }
  }

  /**
   * Create a [[CalendarInterval]] literal expression. An interval expression can contain multiple
   * unit value pairs, for instance: interval 2 months 2 days.
   */
  override def visitInterval(ctx: IntervalContext): Literal = withOrigin(ctx) {
    val intervals = ctx.intervalField.asScala.map(visitIntervalField)
    validate(intervals.nonEmpty, "at least one time unit should be given for interval literal", ctx)
    Literal(intervals.reduce(_.add(_)))
  }

  /**
   * Create a [[CalendarInterval]] for a unit value pair. Two unit configuration types are
   * supported:
   * - Single unit.
   * - From-To unit ('YEAR TO MONTH', 'DAY TO HOUR', 'DAY TO MINUTE', 'DAY TO SECOND',
   * 'HOUR TO MINUTE', 'HOUR TO SECOND' and 'MINUTE TO SECOND' are supported).
   */
  override def visitIntervalField(ctx: IntervalFieldContext): CalendarInterval = withOrigin(ctx) {
    import ctx._
    val s = value.getText
    try {
      val unitText = unit.getText.toLowerCase(Locale.ROOT)
      val interval = (unitText, Option(to).map(_.getText.toLowerCase(Locale.ROOT))) match {
        case (u, None) if u.endsWith("s") =>
          // Handle plural forms, e.g: yearS/monthS/weekS/dayS/hourS/minuteS/hourS/...
          CalendarInterval.fromSingleUnitString(u.substring(0, u.length - 1), s)
        case (u, None) =>
          CalendarInterval.fromSingleUnitString(u, s)
        case ("year", Some("month")) =>
          CalendarInterval.fromYearMonthString(s)
        case ("day", Some("hour")) =>
          CalendarInterval.fromDayTimeString(s, "day", "hour")
        case ("day", Some("minute")) =>
          CalendarInterval.fromDayTimeString(s, "day", "minute")
        case ("day", Some("second")) =>
          CalendarInterval.fromDayTimeString(s, "day", "second")
        case ("hour", Some("minute")) =>
          CalendarInterval.fromDayTimeString(s, "hour", "minute")
        case ("hour", Some("second")) =>
          CalendarInterval.fromDayTimeString(s, "hour", "second")
        case ("minute", Some("second")) =>
          CalendarInterval.fromDayTimeString(s, "minute", "second")
        case (from, Some(t)) =>
          throw new ParseException(s"Intervals FROM $from TO $t are not supported.", ctx)
      }
      validate(interval != null, "No interval can be constructed", ctx)
      interval
    } catch {
      // Handle Exceptions thrown by CalendarInterval
      case e: IllegalArgumentException =>
        val pe = new ParseException(e.getMessage, ctx)
        pe.setStackTrace(e.getStackTrace)
        throw pe
    }
  }

  /* ********************************************************************************************
   * DataType parsing
   * ******************************************************************************************** */
  /**
   * Create a Spark DataType.
   */
  private def visitSparkDataType(ctx: DataTypeContext): DataType = {
    HiveStringType.replaceCharType(typedVisit(ctx))
  }

  /**
   * Resolve/create a primitive type.
   */
  override def visitPrimitiveDataType(ctx: PrimitiveDataTypeContext): DataType = withOrigin(ctx) {
    val dataType = ctx.identifier.getText.toLowerCase(Locale.ROOT)
    (dataType, ctx.INTEGER_VALUE().asScala.toList) match {
      case ("boolean", Nil) => BooleanType
      case ("tinyint" | "byte", Nil) => ByteType
      case ("smallint" | "short", Nil) => ShortType
      case ("int" | "integer", Nil) => IntegerType
      case ("bigint" | "long", Nil) => LongType
      case ("float", Nil) => FloatType
      case ("double", Nil) => DoubleType
      case ("date", Nil) => DateType
      case ("timestamp", Nil) => TimestampType
      case ("string", Nil) => StringType
      case ("char", length :: Nil) => CharType(length.getText.toInt)
      case ("varchar", length :: Nil) => VarcharType(length.getText.toInt)
      case ("binary", Nil) => BinaryType
      case ("decimal", Nil) => DecimalType.USER_DEFAULT
      case ("decimal", precision :: Nil) => DecimalType(precision.getText.toInt, 0)
      case ("decimal", precision :: scale :: Nil) =>
        DecimalType(precision.getText.toInt, scale.getText.toInt)
      case ("interval", Nil) => CalendarIntervalType
      case (dt, params) =>
        val dtStr = if (params.nonEmpty) s"$dt(${params.mkString(",")})" else dt
        throw new ParseException(s"DataType $dtStr is not supported.", ctx)
    }
  }

  /**
   * Create a complex DataType. Arrays, Maps and Structures are supported.
   */
  override def visitComplexDataType(ctx: ComplexDataTypeContext): DataType = withOrigin(ctx) {
    ctx.complex.getType match {
      case SqlBaseParser.ARRAY =>
        ArrayType(typedVisit(ctx.dataType(0)))
      case SqlBaseParser.MAP =>
        MapType(typedVisit(ctx.dataType(0)), typedVisit(ctx.dataType(1)))
      case SqlBaseParser.STRUCT =>
        StructType(Option(ctx.complexColTypeList).toSeq.flatMap(visitComplexColTypeList))
    }
  }

  /**
   * Create top level table schema.
   */
  protected def createSchema(ctx: ColTypeListContext): StructType = {
    StructType(Option(ctx).toSeq.flatMap(visitColTypeList))
  }

  /**
   * Create a [[StructType]] from a number of column definitions.
   */
  override def visitColTypeList(ctx: ColTypeListContext): Seq[StructField] = withOrigin(ctx) {
    ctx.colType().asScala.map(visitColType)
  }

  /**
   * Create a top level [[StructField]] from a column definition.
   */
  override def visitColType(ctx: ColTypeContext): StructField = withOrigin(ctx) {
    import ctx._

    val builder = new MetadataBuilder
    // Add comment to metadata
    if (STRING != null) {
      builder.putString("comment", string(STRING))
    }
    // Add Hive type string to metadata.
    val rawDataType = typedVisit[DataType](ctx.dataType)
    val cleanedDataType = HiveStringType.replaceCharType(rawDataType)
    if (rawDataType != cleanedDataType) {
      builder.putString(HIVE_TYPE_STRING, rawDataType.catalogString)
    }

    StructField(
      colName.getText,
      cleanedDataType,
      nullable = true,
      builder.build())
  }

  /**
   * Create a [[StructType]] from a sequence of [[StructField]]s.
   */
  protected def createStructType(ctx: ComplexColTypeListContext): StructType = {
    StructType(Option(ctx).toSeq.flatMap(visitComplexColTypeList))
  }

  /**
   * Create a [[StructType]] from a number of column definitions.
   */
  override def visitComplexColTypeList(
      ctx: ComplexColTypeListContext): Seq[StructField] = withOrigin(ctx) {
    ctx.complexColType().asScala.map(visitComplexColType)
  }

  /**
   * Create a [[StructField]] from a column definition.
   */
  override def visitComplexColType(ctx: ComplexColTypeContext): StructField = withOrigin(ctx) {
    import ctx._
    val structField = StructField(identifier.getText, typedVisit(dataType), nullable = true)
    if (STRING == null) structField else structField.withComment(string(STRING))
  }

  /**
   * Create location string.
   */
  override def visitLocationSpec(ctx: LocationSpecContext): String = withOrigin(ctx) {
    string(ctx.STRING)
  }

  /**
   * Create a [[BucketSpec]].
   */
  override def visitBucketSpec(ctx: BucketSpecContext): BucketSpec = withOrigin(ctx) {
    BucketSpec(
      ctx.INTEGER_VALUE.getText.toInt,
      visitIdentifierList(ctx.identifierList),
      Option(ctx.orderedIdentifierList)
          .toSeq
          .flatMap(_.orderedIdentifier.asScala)
          .map { orderedIdCtx =>
            Option(orderedIdCtx.ordering).map(_.getText).foreach { dir =>
              if (dir.toLowerCase(Locale.ROOT) != "asc") {
                operationNotAllowed(s"Column ordering must be ASC, was '$dir'", ctx)
              }
            }

            orderedIdCtx.ident.getText
          })
  }

  /**
   * Convert a table property list into a key-value map.
   * This should be called through [[visitPropertyKeyValues]] or [[visitPropertyKeys]].
   */
  override def visitTablePropertyList(
      ctx: TablePropertyListContext): Map[String, String] = withOrigin(ctx) {
    val properties = ctx.tableProperty.asScala.map { property =>
      val key = visitTablePropertyKey(property.key)
      val value = visitTablePropertyValue(property.value)
      key -> value
    }
    // Check for duplicate property names.
    checkDuplicateKeys(properties, ctx)
    properties.toMap
  }

  /**
   * Parse a key-value map from a [[TablePropertyListContext]], assuming all values are specified.
   */
  def visitPropertyKeyValues(ctx: TablePropertyListContext): Map[String, String] = {
    val props = visitTablePropertyList(ctx)
    val badKeys = props.collect { case (key, null) => key }
    if (badKeys.nonEmpty) {
      operationNotAllowed(
        s"Values must be specified for key(s): ${badKeys.mkString("[", ",", "]")}", ctx)
    }
    props
  }

  /**
   * Parse a list of keys from a [[TablePropertyListContext]], assuming no values are specified.
   */
  def visitPropertyKeys(ctx: TablePropertyListContext): Seq[String] = {
    val props = visitTablePropertyList(ctx)
    val badKeys = props.filter { case (_, v) => v != null }.keys
    if (badKeys.nonEmpty) {
      operationNotAllowed(
        s"Values should not be specified for key(s): ${badKeys.mkString("[", ",", "]")}", ctx)
    }
    props.keys.toSeq
  }

  /**
   * A table property key can either be String or a collection of dot separated elements. This
   * function extracts the property key based on whether its a string literal or a table property
   * identifier.
   */
  override def visitTablePropertyKey(key: TablePropertyKeyContext): String = {
    if (key.STRING != null) {
      string(key.STRING)
    } else {
      key.getText
    }
  }

  /**
   * A table property value can be String, Integer, Boolean or Decimal. This function extracts
   * the property value based on whether its a string, integer, boolean or decimal literal.
   */
  override def visitTablePropertyValue(value: TablePropertyValueContext): String = {
    if (value == null) {
      null
    } else if (value.STRING != null) {
      string(value.STRING)
    } else if (value.booleanValue != null) {
      value.getText.toLowerCase(Locale.ROOT)
    } else {
      value.getText
    }
  }

  /**
   * Type to keep track of a table header: (identifier, isTemporary, ifNotExists, isExternal).
   */
  type TableHeader = (Seq[String], Boolean, Boolean, Boolean)

  /**
   * Validate a create table statement and return the [[TableIdentifier]].
   */
  override def visitCreateTableHeader(
      ctx: CreateTableHeaderContext): TableHeader = withOrigin(ctx) {
    val temporary = ctx.TEMPORARY != null
    val ifNotExists = ctx.EXISTS != null
    if (temporary && ifNotExists) {
      operationNotAllowed("CREATE TEMPORARY TABLE ... IF NOT EXISTS", ctx)
    }
    val multipartIdentifier = ctx.multipartIdentifier.parts.asScala.map(_.getText)
    (multipartIdentifier, temporary, ifNotExists, ctx.EXTERNAL != null)
  }

  /**
   * Validate a replace table statement and return the [[TableIdentifier]].
   */
  override def visitReplaceTableHeader(
      ctx: ReplaceTableHeaderContext): TableHeader = withOrigin(ctx) {
    val multipartIdentifier = ctx.multipartIdentifier.parts.asScala.map(_.getText)
    (multipartIdentifier, false, false, false)
  }

  /**
   * Parse a qualified name to a multipart name.
   */
  override def visitQualifiedName(ctx: QualifiedNameContext): Seq[String] = withOrigin(ctx) {
    ctx.identifier.asScala.map(_.getText)
  }

  /**
   * Parse a list of transforms.
   */
  override def visitTransformList(ctx: TransformListContext): Seq[Transform] = withOrigin(ctx) {
    def getFieldReference(
        ctx: ApplyTransformContext,
        arg: V2Expression): FieldReference = {
      lazy val name: String = ctx.identifier.getText
      arg match {
        case ref: FieldReference =>
          ref
        case nonRef =>
          throw new ParseException(
            s"Expected a column reference for transform $name: ${nonRef.describe}", ctx)
      }
    }

    def getSingleFieldReference(
        ctx: ApplyTransformContext,
        arguments: Seq[V2Expression]): FieldReference = {
      lazy val name: String = ctx.identifier.getText
      if (arguments.size > 1) {
        throw new ParseException(s"Too many arguments for transform $name", ctx)
      } else if (arguments.isEmpty) {
        throw new ParseException(s"Not enough arguments for transform $name", ctx)
      } else {
        getFieldReference(ctx, arguments.head)
      }
    }

    ctx.transforms.asScala.map {
      case identityCtx: IdentityTransformContext =>
        IdentityTransform(FieldReference(typedVisit[Seq[String]](identityCtx.qualifiedName)))

      case applyCtx: ApplyTransformContext =>
        val arguments = applyCtx.argument.asScala.map(visitTransformArgument)

        applyCtx.identifier.getText match {
          case "bucket" =>
            val numBuckets: Int = arguments.head match {
              case LiteralValue(shortValue, ShortType) =>
                shortValue.asInstanceOf[Short].toInt
              case LiteralValue(intValue, IntegerType) =>
                intValue.asInstanceOf[Int]
              case LiteralValue(longValue, LongType) =>
                longValue.asInstanceOf[Long].toInt
              case lit =>
                throw new ParseException(s"Invalid number of buckets: ${lit.describe}", applyCtx)
            }

            val fields = arguments.tail.map(arg => getFieldReference(applyCtx, arg))

            BucketTransform(LiteralValue(numBuckets, IntegerType), fields)

          case "years" =>
            YearsTransform(getSingleFieldReference(applyCtx, arguments))

          case "months" =>
            MonthsTransform(getSingleFieldReference(applyCtx, arguments))

          case "days" =>
            DaysTransform(getSingleFieldReference(applyCtx, arguments))

          case "hours" =>
            HoursTransform(getSingleFieldReference(applyCtx, arguments))

          case name =>
            ApplyTransform(name, arguments)
        }
    }
  }

  /**
   * Parse an argument to a transform. An argument may be a field reference (qualified name) or
   * a value literal.
   */
  override def visitTransformArgument(ctx: TransformArgumentContext): V2Expression = {
    withOrigin(ctx) {
      val reference = Option(ctx.qualifiedName)
          .map(typedVisit[Seq[String]])
          .map(FieldReference(_))
      val literal = Option(ctx.constant)
          .map(typedVisit[Literal])
          .map(lit => LiteralValue(lit.value, lit.dataType))
      reference.orElse(literal)
          .getOrElse(throw new ParseException(s"Invalid transform argument", ctx))
    }
  }

  /**
   * Create a [[ShowNamespacesStatement]] command.
   */
  override def visitShowNamespaces(ctx: ShowNamespacesContext): LogicalPlan = withOrigin(ctx) {
    if (ctx.DATABASES != null && ctx.multipartIdentifier != null) {
      throw new ParseException(s"FROM/IN operator is not allowed in SHOW DATABASES", ctx)
    }

    ShowNamespacesStatement(
      Option(ctx.multipartIdentifier).map(visitMultipartIdentifier),
      Option(ctx.pattern).map(string))
  }

  /**
   * Create a table, returning a [[CreateTableStatement]] logical plan.
   *
   * Expected format:
   * {{{
   *   CREATE [TEMPORARY] TABLE [IF NOT EXISTS] [db_name.]table_name
   *   USING table_provider
   *   create_table_clauses
   *   [[AS] select_statement];
   *
   *   create_table_clauses (order insensitive):
   *     [OPTIONS table_property_list]
   *     [PARTITIONED BY (col_name, transform(col_name), transform(constant, col_name), ...)]
   *     [CLUSTERED BY (col_name, col_name, ...)
   *       [SORTED BY (col_name [ASC|DESC], ...)]
   *       INTO num_buckets BUCKETS
   *     ]
   *     [LOCATION path]
   *     [COMMENT table_comment]
   *     [TBLPROPERTIES (property_name=property_value, ...)]
   * }}}
   */
  override def visitCreateTable(ctx: CreateTableContext): LogicalPlan = withOrigin(ctx) {
    val (table, temp, ifNotExists, external) = visitCreateTableHeader(ctx.createTableHeader)
    if (external) {
      operationNotAllowed("CREATE EXTERNAL TABLE ... USING", ctx)
    }

    checkDuplicateClauses(ctx.TBLPROPERTIES, "TBLPROPERTIES", ctx)
    checkDuplicateClauses(ctx.OPTIONS, "OPTIONS", ctx)
    checkDuplicateClauses(ctx.PARTITIONED, "PARTITIONED BY", ctx)
    checkDuplicateClauses(ctx.COMMENT, "COMMENT", ctx)
    checkDuplicateClauses(ctx.bucketSpec(), "CLUSTERED BY", ctx)
    checkDuplicateClauses(ctx.locationSpec, "LOCATION", ctx)

    val schema = Option(ctx.colTypeList()).map(createSchema)
    val partitioning: Seq[Transform] =
      Option(ctx.partitioning).map(visitTransformList).getOrElse(Nil)
    val bucketSpec = ctx.bucketSpec().asScala.headOption.map(visitBucketSpec)
    val properties = Option(ctx.tableProps).map(visitPropertyKeyValues).getOrElse(Map.empty)
    val options = Option(ctx.options).map(visitPropertyKeyValues).getOrElse(Map.empty)

    val provider = ctx.tableProvider.qualifiedName.getText
    val location = ctx.locationSpec.asScala.headOption.map(visitLocationSpec)
    val comment = Option(ctx.comment).map(string)

    Option(ctx.query).map(plan) match {
      case Some(_) if temp =>
        operationNotAllowed("CREATE TEMPORARY TABLE ... USING ... AS query", ctx)

      case Some(_) if schema.isDefined =>
        operationNotAllowed(
          "Schema may not be specified in a Create Table As Select (CTAS) statement",
          ctx)

      case Some(query) =>
        CreateTableAsSelectStatement(
          table, query, partitioning, bucketSpec, properties, provider, options, location, comment,
          ifNotExists = ifNotExists)

      case None if temp =>
        // CREATE TEMPORARY TABLE ... USING ... is not supported by the catalyst parser.
        // Use CREATE TEMPORARY VIEW ... USING ... instead.
        operationNotAllowed("CREATE TEMPORARY TABLE IF NOT EXISTS", ctx)

      case _ =>
        CreateTableStatement(table, schema.getOrElse(new StructType), partitioning, bucketSpec,
          properties, provider, options, location, comment, ifNotExists = ifNotExists)
    }
  }

  /**
   * Replace a table, returning a [[ReplaceTableStatement]] logical plan.
   *
   * Expected format:
   * {{{
   *   [CREATE OR] REPLACE TABLE [db_name.]table_name
   *   USING table_provider
   *   replace_table_clauses
   *   [[AS] select_statement];
   *
   *   replace_table_clauses (order insensitive):
   *     [OPTIONS table_property_list]
   *     [PARTITIONED BY (col_name, transform(col_name), transform(constant, col_name), ...)]
   *     [CLUSTERED BY (col_name, col_name, ...)
   *       [SORTED BY (col_name [ASC|DESC], ...)]
   *       INTO num_buckets BUCKETS
   *     ]
   *     [LOCATION path]
   *     [COMMENT table_comment]
   *     [TBLPROPERTIES (property_name=property_value, ...)]
   * }}}
   */
  override def visitReplaceTable(ctx: ReplaceTableContext): LogicalPlan = withOrigin(ctx) {
    val (table, _, ifNotExists, external) = visitReplaceTableHeader(ctx.replaceTableHeader)
    if (external) {
      operationNotAllowed("REPLACE EXTERNAL TABLE ... USING", ctx)
    }

    checkDuplicateClauses(ctx.TBLPROPERTIES, "TBLPROPERTIES", ctx)
    checkDuplicateClauses(ctx.OPTIONS, "OPTIONS", ctx)
    checkDuplicateClauses(ctx.PARTITIONED, "PARTITIONED BY", ctx)
    checkDuplicateClauses(ctx.COMMENT, "COMMENT", ctx)
    checkDuplicateClauses(ctx.bucketSpec(), "CLUSTERED BY", ctx)
    checkDuplicateClauses(ctx.locationSpec, "LOCATION", ctx)

    val schema = Option(ctx.colTypeList()).map(createSchema)
    val partitioning: Seq[Transform] =
      Option(ctx.partitioning).map(visitTransformList).getOrElse(Nil)
    val bucketSpec = ctx.bucketSpec().asScala.headOption.map(visitBucketSpec)
    val properties = Option(ctx.tableProps).map(visitPropertyKeyValues).getOrElse(Map.empty)
    val options = Option(ctx.options).map(visitPropertyKeyValues).getOrElse(Map.empty)

    val provider = ctx.tableProvider.qualifiedName.getText
    val location = ctx.locationSpec.asScala.headOption.map(visitLocationSpec)
    val comment = Option(ctx.comment).map(string)
    val orCreate = ctx.replaceTableHeader().CREATE() != null

    Option(ctx.query).map(plan) match {
      case Some(_) if schema.isDefined =>
        operationNotAllowed(
          "Schema may not be specified in a Replace Table As Select (RTAS) statement",
          ctx)

      case Some(query) =>
        ReplaceTableAsSelectStatement(table, query, partitioning, bucketSpec, properties,
          provider, options, location, comment, orCreate = orCreate)

      case _ =>
        ReplaceTableStatement(table, schema.getOrElse(new StructType), partitioning,
          bucketSpec, properties, provider, options, location, comment, orCreate = orCreate)
    }
  }

  /**
   * Create a [[DropTableStatement]] command.
   */
  override def visitDropTable(ctx: DropTableContext): LogicalPlan = withOrigin(ctx) {
    DropTableStatement(
      visitMultipartIdentifier(ctx.multipartIdentifier()),
      ctx.EXISTS != null,
      ctx.PURGE != null)
  }

  /**
   * Create a [[DropViewStatement]] command.
   */
  override def visitDropView(ctx: DropViewContext): AnyRef = withOrigin(ctx) {
    DropViewStatement(
      visitMultipartIdentifier(ctx.multipartIdentifier()),
      ctx.EXISTS != null)
  }

  /**
   * Create a [[UseStatement]] logical plan.
   */
  override def visitUse(ctx: UseContext): LogicalPlan = withOrigin(ctx) {
    val nameParts = visitMultipartIdentifier(ctx.multipartIdentifier)
    UseStatement(ctx.NAMESPACE != null, nameParts)
  }

  /**
   * Create a [[ShowTablesStatement]] command.
   */
  override def visitShowTables(ctx: ShowTablesContext): LogicalPlan = withOrigin(ctx) {
    ShowTablesStatement(
      Option(ctx.multipartIdentifier).map(visitMultipartIdentifier),
      Option(ctx.pattern).map(string))
  }

  /**
   * Parse new column info from ADD COLUMN into a QualifiedColType.
   */
  override def visitQualifiedColTypeWithPosition(
      ctx: QualifiedColTypeWithPositionContext): QualifiedColType = withOrigin(ctx) {
    if (ctx.colPosition != null) {
      operationNotAllowed("ALTER TABLE table ADD COLUMN ... FIRST | AFTER otherCol", ctx)
    }

    QualifiedColType(
      typedVisit[Seq[String]](ctx.name),
      typedVisit[DataType](ctx.dataType),
      Option(ctx.comment).map(string))
  }

  /**
   * Parse a [[AlterTableAddColumnsStatement]] command.
   *
   * For example:
   * {{{
   *   ALTER TABLE table1
   *   ADD COLUMNS (col_name data_type [COMMENT col_comment], ...);
   * }}}
   */
  override def visitAddTableColumns(ctx: AddTableColumnsContext): LogicalPlan = withOrigin(ctx) {
    AlterTableAddColumnsStatement(
      visitMultipartIdentifier(ctx.multipartIdentifier),
      ctx.columns.qualifiedColTypeWithPosition.asScala.map(typedVisit[QualifiedColType])
    )
  }

  /**
   * Parse a [[AlterTableRenameColumnStatement]] command.
   *
   * For example:
   * {{{
   *   ALTER TABLE table1 RENAME COLUMN a.b.c TO x
   * }}}
   */
  override def visitRenameTableColumn(
      ctx: RenameTableColumnContext): LogicalPlan = withOrigin(ctx) {
    AlterTableRenameColumnStatement(
      visitMultipartIdentifier(ctx.multipartIdentifier),
      ctx.from.identifier.asScala.map(_.getText),
      ctx.to.getText)
  }

  /**
   * Parse a [[AlterTableAlterColumnStatement]] command.
   *
   * For example:
   * {{{
   *   ALTER TABLE table1 ALTER COLUMN a.b.c TYPE bigint
   *   ALTER TABLE table1 ALTER COLUMN a.b.c TYPE bigint COMMENT 'new comment'
   *   ALTER TABLE table1 ALTER COLUMN a.b.c COMMENT 'new comment'
   * }}}
   */
  override def visitAlterTableColumn(
      ctx: AlterTableColumnContext): LogicalPlan = withOrigin(ctx) {
    val verb = if (ctx.CHANGE != null) "CHANGE" else "ALTER"
    if (ctx.colPosition != null) {
      operationNotAllowed(s"ALTER TABLE table $verb COLUMN ... FIRST | AFTER otherCol", ctx)
    }

    if (ctx.dataType == null && ctx.comment == null) {
      operationNotAllowed(s"ALTER TABLE table $verb COLUMN requires a TYPE or a COMMENT", ctx)
    }

    AlterTableAlterColumnStatement(
      visitMultipartIdentifier(ctx.multipartIdentifier),
      typedVisit[Seq[String]](ctx.qualifiedName),
      Option(ctx.dataType).map(typedVisit[DataType]),
      Option(ctx.comment).map(string))
  }

  /**
   * Parse a [[AlterTableDropColumnsStatement]] command.
   *
   * For example:
   * {{{
   *   ALTER TABLE table1 DROP COLUMN a.b.c
   *   ALTER TABLE table1 DROP COLUMNS a.b.c, x, y
   * }}}
   */
  override def visitDropTableColumns(
      ctx: DropTableColumnsContext): LogicalPlan = withOrigin(ctx) {
    val columnsToDrop = ctx.columns.qualifiedName.asScala.map(typedVisit[Seq[String]])
    AlterTableDropColumnsStatement(
      visitMultipartIdentifier(ctx.multipartIdentifier),
      columnsToDrop)
  }

  /**
   * Parse [[AlterViewSetPropertiesStatement]] or [[AlterTableSetPropertiesStatement]] commands.
   *
   * For example:
   * {{{
   *   ALTER TABLE table SET TBLPROPERTIES ('comment' = new_comment);
   *   ALTER VIEW view SET TBLPROPERTIES ('comment' = new_comment);
   * }}}
   */
  override def visitSetTableProperties(
      ctx: SetTablePropertiesContext): LogicalPlan = withOrigin(ctx) {
    val identifier = visitMultipartIdentifier(ctx.multipartIdentifier)
    val properties = visitPropertyKeyValues(ctx.tablePropertyList)
    if (ctx.VIEW != null) {
      AlterViewSetPropertiesStatement(identifier, properties)
    } else {
      AlterTableSetPropertiesStatement(identifier, properties)
    }
  }

  /**
   * Parse [[AlterViewUnsetPropertiesStatement]] or [[AlterTableUnsetPropertiesStatement]] commands.
   *
   * For example:
   * {{{
   *   ALTER TABLE table UNSET TBLPROPERTIES [IF EXISTS] ('comment', 'key');
   *   ALTER VIEW view UNSET TBLPROPERTIES [IF EXISTS] ('comment', 'key');
   * }}}
   */
  override def visitUnsetTableProperties(
      ctx: UnsetTablePropertiesContext): LogicalPlan = withOrigin(ctx) {
    val identifier = visitMultipartIdentifier(ctx.multipartIdentifier)
    val properties = visitPropertyKeys(ctx.tablePropertyList)
    val ifExists = ctx.EXISTS != null
    if (ctx.VIEW != null) {
      AlterViewUnsetPropertiesStatement(identifier, properties, ifExists)
    } else {
      AlterTableUnsetPropertiesStatement(identifier, properties, ifExists)
    }
  }

  /**
   * Create an [[AlterTableSetLocationStatement]] command.
   *
   * For example:
   * {{{
   *   ALTER TABLE table SET LOCATION "loc";
   * }}}
   */
  override def visitSetTableLocation(ctx: SetTableLocationContext): LogicalPlan = withOrigin(ctx) {
    AlterTableSetLocationStatement(
      visitMultipartIdentifier(ctx.multipartIdentifier),
      visitLocationSpec(ctx.locationSpec))
  }

  /**
   * Create a [[DescribeColumnStatement]] or [[DescribeTableStatement]] commands.
   */
  override def visitDescribeTable(ctx: DescribeTableContext): LogicalPlan = withOrigin(ctx) {
    val isExtended = ctx.EXTENDED != null || ctx.FORMATTED != null
    if (ctx.describeColName != null) {
      if (ctx.partitionSpec != null) {
        throw new ParseException("DESC TABLE COLUMN for a specific partition is not supported", ctx)
      } else {
        DescribeColumnStatement(
          visitMultipartIdentifier(ctx.multipartIdentifier()),
          ctx.describeColName.nameParts.asScala.map(_.getText),
          isExtended)
      }
    } else {
      val partitionSpec = if (ctx.partitionSpec != null) {
        // According to the syntax, visitPartitionSpec returns `Map[String, Option[String]]`.
        visitPartitionSpec(ctx.partitionSpec).map {
          case (key, Some(value)) => key -> value
          case (key, _) =>
            throw new ParseException(s"PARTITION specification is incomplete: `$key`", ctx)
        }
      } else {
        Map.empty[String, String]
      }
      DescribeTableStatement(
        visitMultipartIdentifier(ctx.multipartIdentifier()),
        partitionSpec,
        isExtended)
    }
  }
}