[SPARK-17760][SQL] AnalysisException with dataframe pivot when groupBy column is not attribute

## What changes were proposed in this pull request?

Fixes AnalysisException for pivot queries that have group by columns that are expressions and not attributes by substituting the expressions output attribute in the second aggregation and final projection.

## How was this patch tested?

existing and additional unit tests

Author: Andrew Ray <ray.andrew@gmail.com>

Closes #16177 from aray/SPARK-17760.

2 files changed, 11 insertions, 2 deletions

diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/Analyzer.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/Analyzer.scala
index ed6e17a8eb..58f98d529a 100644
--- a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/Analyzer.scala
+++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/Analyzer.scala
@@ -463,14 +463,15 @@ class Analyzer(
               .toAggregateExpression()
             , "__pivot_" + a.sql)()
           }
-          val secondAgg = Aggregate(groupByExprs, groupByExprs ++ pivotAggs, firstAgg)
+          val groupByExprsAttr = groupByExprs.map(_.toAttribute)
+          val secondAgg = Aggregate(groupByExprsAttr, groupByExprsAttr ++ pivotAggs, firstAgg)
           val pivotAggAttribute = pivotAggs.map(_.toAttribute)
           val pivotOutputs = pivotValues.zipWithIndex.flatMap { case (value, i) =>
             aggregates.zip(pivotAggAttribute).map { case (aggregate, pivotAtt) =>
               Alias(ExtractValue(pivotAtt, Literal(i), resolver), outputName(value, aggregate))()
             }
           }
-          Project(groupByExprs ++ pivotOutputs, secondAgg)
+          Project(groupByExprsAttr ++ pivotOutputs, secondAgg)
         } else {
           val pivotAggregates: Seq[NamedExpression] = pivotValues.flatMap { value =>
             def ifExpr(expr: Expression) = {
diff --git a/sql/core/src/test/scala/org/apache/spark/sql/DataFramePivotSuite.scala b/sql/core/src/test/scala/org/apache/spark/sql/DataFramePivotSuite.scala
index 1bbe1354d5..a8d854ccbc 100644
--- a/sql/core/src/test/scala/org/apache/spark/sql/DataFramePivotSuite.scala
+++ b/sql/core/src/test/scala/org/apache/spark/sql/DataFramePivotSuite.scala
@@ -208,4 +208,12 @@ class DataFramePivotSuite extends QueryTest with SharedSQLContext{
     )
   }
 
+  test("pivot with column definition in groupby") {
+    checkAnswer(
+      courseSales.groupBy(substring(col("course"), 0, 1).as("foo"))
+        .pivot("year", Seq(2012, 2013))
+        .sum("earnings"),
+      Row("d", 15000.0, 48000.0) :: Row("J", 20000.0, 30000.0) :: Nil
+    )
+  }
 }