some enhance

apache · Sep 10, 2014 · 16bc4c6 · 16bc4c6
1 parent 95d733f
commit 16bc4c6
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Showing 2 changed files with 14 additions and 5 deletions.
diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/SqlParser.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/SqlParser.scala
@@ -357,7 +357,6 @@ class SqlParser extends StandardTokenParsers with PackratParsers {
     expression ~ "[" ~ expression <~ "]" ^^ {
       case base ~ _ ~ ordinal => GetItem(base, ordinal)
     } |
-    dotExpressionHeader |
     expression ~ "." ~ ident ^^ {
       case base ~ _ ~ fieldName => GetField(base, fieldName)
     } |
@@ -367,6 +366,7 @@ class SqlParser extends StandardTokenParsers with PackratParsers {
     "(" ~> expression <~ ")" |
     function |
     "-" ~> literal ^^ UnaryMinus |
+    dotExpressionHeader |
     ident ^^ UnresolvedAttribute |
     "*" ^^^ Star(None) |
     literal

diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/plans/logical/LogicalPlan.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/plans/logical/LogicalPlan.scala
@@ -86,10 +86,13 @@ abstract class LogicalPlan extends QueryPlan[LogicalPlan] {
   def resolve(name: String): Option[NamedExpression] =
     resolve(name, output)
 
-  /** Performs attribute resolution given a name and a sequence of possible attributes. */
+  /**
+   * Performs attribute resolution given a name and a sequence of possible attributes.
+   * The only possible formats of name are "ident" and "ident.ident".
+   */
   protected def resolve(name: String, input: Seq[Attribute]): Option[NamedExpression] = {
     def handleResult[A <: NamedExpression](result: Seq[A]) = {
-      result match {
+      result.distinct match {
         case Seq(a) => Some(a)
         case Seq() => None
         case ambiguousReferences =>
@@ -99,13 +102,19 @@ abstract class LogicalPlan extends QueryPlan[LogicalPlan] {
     }
 
     name.split("\\.") match {
+      // the format of name is "ident", it should match the name of a possible attribute
       case Array(s) => handleResult(input.filter(_.name == s))
+
+      // The format of name is "ident.ident", the first part should matches the scope
+      // and the second part should matches the name. Or the first part matches the
+      // name and this attribute is struct type.
       case Array(s1, s2) =>
         handleResult(input.collect {
-          case a if a.qualifiers.contains(s1) && a.name == s2 => a
-          case a if a.name == s1 && a.dataType.isInstanceOf[StructType] =>
+          case a if (a.qualifiers.contains(s1) && a.name == s2) => a
+          case a if (a.name == s1 && a.dataType.isInstanceOf[StructType]) =>
             Alias(GetField(a, s2), s2)()
         })
+
       case _ => None
     }
   }