SQL: Add PARSE_LONG function. (#7326)

* SQL: Add PARSE_LONG function.

* Fix test.

core/src/main/java/org/apache/druid/math/expr/Function.java

@@ -122,6 +122,48 @@ protected ExprEval eval(double x, double y)
     }
   }
 
+  class ParseLong implements Function
+  {
+    @Override
+    public String name()
+    {
+      return "parse_long";
+    }
+
+    @Override
+    public ExprEval apply(List<Expr> args, Expr.ObjectBinding bindings)
+    {
+      final int radix;
+      if (args.size() == 1) {
+        radix = 10;
+      } else if (args.size() == 2) {
+        radix = args.get(1).eval(bindings).asInt();
+      } else {
+        throw new IAE("Function[%s] needs 1 or 2 arguments", name());
+      }
+
+      final String input = NullHandling.nullToEmptyIfNeeded(args.get(0).eval(bindings).asString());
+      if (input == null) {
+        return ExprEval.ofLong(null);
+      }
+
+      final long retVal;
+      try {
+        if (radix == 16 && (input.startsWith("0x") || input.startsWith("0X"))) {
+          // Strip leading 0x from hex strings.
+          retVal = Long.parseLong(input.substring(2), radix);
+        } else {
+          retVal = Long.parseLong(input, radix);
+        }
+      }
+      catch (NumberFormatException e) {
+        return ExprEval.ofLong(null);
+      }
+
+      return ExprEval.of(retVal);
+    }
+  }
+
   class Pi implements Function
   {
     private static final double PI = Math.PI;

docs/content/misc/math-expr.md

@@ -69,6 +69,7 @@ The following built-in functions are available.
 |concat|concatenate a list of strings|
 |like|like(expr, pattern[, escape]) is equivalent to SQL `expr LIKE pattern`|
 |lookup|lookup(expr, lookup-name) looks up expr in a registered [query-time lookup](../querying/lookups.html)|
+|parse_long|parse_long(string[, radix]) parses a string as a long with the given radix, or 10 (decimal) if a radix is not provided.|
 |regexp_extract|regexp_extract(expr, pattern[, index]) applies a regular expression pattern and extracts a capture group index, or null if there is no match. If index is unspecified or zero, returns the substring that matched the pattern.|
 |replace|replace(expr, pattern, replacement) replaces pattern with replacement|
 |substring|substring(expr, index, length) behaves like java.lang.String's substring|

docs/content/querying/sql.md

@@ -178,6 +178,7 @@ String functions accept strings, and return a type appropriate to the function.
 |`STRLEN(expr)`|Synonym for `LENGTH`.|
 |`LOOKUP(expr, lookupName)`|Look up expr in a registered [query-time lookup table](lookups.html).|
 |`LOWER(expr)`|Returns expr in all lowercase.|
+|`PARSE_LONG(string[, radix])`|Parses a string into a long (BIGINT) with the given radix, or 10 (decimal) if a radix is not provided.|
 |`POSITION(needle IN haystack [FROM fromIndex])`|Returns the index of needle within haystack, with indexes starting from 1. The search will begin at fromIndex, or 1 if fromIndex is not specified. If the needle is not found, returns 0.|
 |`REGEXP_EXTRACT(expr, pattern, [index])`|Apply regular expression pattern and extract a capture group, or null if there is no match. If index is unspecified or zero, returns the substring that matched the pattern.|
 |`REPLACE(expr, pattern, replacement)`|Replaces pattern with replacement in expr, and returns the result.|

sql/src/main/java/org/apache/druid/sql/calcite/expression/builtin/ParseLongOperatorConversion.java

@@ -0,0 +1,61 @@
+/*
+ * 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.druid.sql.calcite.expression.builtin;
+
+import org.apache.calcite.rex.RexNode;
+import org.apache.calcite.sql.SqlFunction;
+import org.apache.calcite.sql.SqlFunctionCategory;
+import org.apache.calcite.sql.SqlOperator;
+import org.apache.calcite.sql.type.SqlTypeFamily;
+import org.apache.calcite.sql.type.SqlTypeName;
+import org.apache.druid.sql.calcite.expression.DruidExpression;
+import org.apache.druid.sql.calcite.expression.OperatorConversions;
+import org.apache.druid.sql.calcite.expression.SqlOperatorConversion;
+import org.apache.druid.sql.calcite.planner.PlannerContext;
+import org.apache.druid.sql.calcite.table.RowSignature;
+
+public class ParseLongOperatorConversion implements SqlOperatorConversion
+{
+  private static final String NAME = "PARSE_LONG";
+
+  private static final SqlFunction SQL_FUNCTION = OperatorConversions
+      .operatorBuilder(NAME)
+      .operandTypes(SqlTypeFamily.CHARACTER, SqlTypeFamily.INTEGER)
+      .returnType(SqlTypeName.BIGINT)
+      .functionCategory(SqlFunctionCategory.STRING)
+      .requiredOperands(1)
+      .build();
+
+  @Override
+  public SqlOperator calciteOperator()
+  {
+    return SQL_FUNCTION;
+  }
+
+  @Override
+  public DruidExpression toDruidExpression(
+      final PlannerContext plannerContext,
+      final RowSignature rowSignature,
+      final RexNode rexNode
+  )
+  {
+    return OperatorConversions.convertCall(plannerContext, rowSignature, rexNode, "parse_long");
+  }
+}

sql/src/main/java/org/apache/druid/sql/calcite/planner/DruidOperatorTable.java

@@ -56,6 +56,7 @@
 import org.apache.druid.sql.calcite.expression.builtin.LTrimOperatorConversion;
 import org.apache.druid.sql.calcite.expression.builtin.LikeOperatorConversion;
 import org.apache.druid.sql.calcite.expression.builtin.MillisToTimestampOperatorConversion;
+import org.apache.druid.sql.calcite.expression.builtin.ParseLongOperatorConversion;
 import org.apache.druid.sql.calcite.expression.builtin.PositionOperatorConversion;
 import org.apache.druid.sql.calcite.expression.builtin.RTrimOperatorConversion;
 import org.apache.druid.sql.calcite.expression.builtin.RegexpExtractOperatorConversion;
@@ -172,6 +173,7 @@ public class DruidOperatorTable implements SqlOperatorTable
           .add(new PositionOperatorConversion())
           .add(new RegexpExtractOperatorConversion())
           .add(new RTrimOperatorConversion())
+          .add(new ParseLongOperatorConversion())
           .add(new StrposOperatorConversion())
           .add(new SubstringOperatorConversion())
           .add(new AliasedOperatorConversion(new SubstringOperatorConversion(), "SUBSTR"))

sql/src/test/java/org/apache/druid/sql/calcite/expression/ExpressionsTest.java

@@ -41,6 +41,7 @@
 import org.apache.druid.query.extraction.RegexDimExtractionFn;
 import org.apache.druid.segment.column.ValueType;
 import org.apache.druid.sql.calcite.expression.builtin.DateTruncOperatorConversion;
+import org.apache.druid.sql.calcite.expression.builtin.ParseLongOperatorConversion;
 import org.apache.druid.sql.calcite.expression.builtin.RegexpExtractOperatorConversion;
 import org.apache.druid.sql.calcite.expression.builtin.StrposOperatorConversion;
 import org.apache.druid.sql.calcite.expression.builtin.TimeExtractOperatorConversion;
@@ -83,6 +84,8 @@ public class ExpressionsTest extends CalciteTestBase
       .add("y", ValueType.LONG)
       .add("z", ValueType.FLOAT)
       .add("s", ValueType.STRING)
+      .add("hexstr", ValueType.STRING)
+      .add("intstr", ValueType.STRING)
       .add("spacey", ValueType.STRING)
       .add("tstr", ValueType.STRING)
       .add("dstr", ValueType.STRING)
@@ -95,6 +98,8 @@ public class ExpressionsTest extends CalciteTestBase
       .put("y", 3.0)
       .put("z", -2.25)
       .put("s", "foo")
+      .put("hexstr", "EF")
+      .put("intstr", "-100")
       .put("spacey", "  hey there  ")
       .put("tstr", "2000-02-03 04:05:06")
       .put("dstr", "2000-02-03")
@@ -198,6 +203,52 @@ public void testStrpos()
     );
   }
 
+  @Test
+  public void testParseLong()
+  {
+    testExpression(
+        rexBuilder.makeCall(
+            new ParseLongOperatorConversion().calciteOperator(),
+            inputRef("intstr")
+        ),
+        DruidExpression.fromExpression("parse_long(\"intstr\")"),
+        -100L
+    );
+
+    testExpression(
+        rexBuilder.makeCall(
+            new ParseLongOperatorConversion().calciteOperator(),
+            inputRef("hexstr"),
+            rexBuilder.makeExactLiteral(BigDecimal.valueOf(16))
+        ),
+        DruidExpression.fromExpression("parse_long(\"hexstr\",16)"),
+        239L
+    );
+
+    testExpression(
+        rexBuilder.makeCall(
+            new ParseLongOperatorConversion().calciteOperator(),
+            rexBuilder.makeCall(
+                SqlStdOperatorTable.CONCAT,
+                rexBuilder.makeLiteral("0x"),
+                inputRef("hexstr")
+            ),
+            rexBuilder.makeExactLiteral(BigDecimal.valueOf(16))
+        ),
+        DruidExpression.fromExpression("parse_long(concat('0x',\"hexstr\"),16)"),
+        239L
+    );
+
+    testExpression(
+        rexBuilder.makeCall(
+            new ParseLongOperatorConversion().calciteOperator(),
+            inputRef("hexstr")
+        ),
+        DruidExpression.fromExpression("parse_long(\"hexstr\")"),
+        NullHandling.sqlCompatible() ? null : 0L
+    );
+  }
+
   @Test
   public void testPosition()
   {