Github user yhuai commented on a diff in the pull request:
https://github.com/apache/spark/pull/7841#discussion_r44489682
--- Diff:
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/Analyzer.scala
---
@@ -247,6 +252,38 @@ class Analyzer(
}
}
+ object ResolvePivot extends Rule[LogicalPlan] {
+ def apply(plan: LogicalPlan): LogicalPlan = plan transform {
+ case p: Pivot if !p.childrenResolved => p
+ case Pivot(groupByExprs, pivotColumn, pivotValues, aggregates,
child) =>
+ val singleAgg = aggregates.size == 1
+ val pivotAggregates: Seq[NamedExpression] = pivotValues.flatMap{
value =>
+ aggregates.map{ aggregate =>
+ val filteredAggregate = aggregate.transformDown{
+ case u: UnaryExpression if
u.isInstanceOf[AggregateExpression] =>
+ u.withNewChildren(Seq(
+ If(EqualTo(pivotColumn, Literal(value)), u.child,
Literal(null))
+ ))
+ case other: AggregateExpression =>
+ throw new AnalysisException(
+ s"Pivot does not support non unary aggregate
expressions, found $other")
+ }
+ if (filteredAggregate.fastEquals(aggregate)) {
+ throw new AnalysisException(
+ s"Unary aggregate expression required for pivot, found
'$aggregate'")
+ }
+ val name = if (singleAgg) value else value + " " +
aggregate.prettyString
--- End diff --
Seems it is always helpful to show the aggregate function(s) that we use
for pivot?
---
If your project is set up for it, you can reply to this email and have your
reply appear on GitHub as well. If your project does not have this feature
enabled and wishes so, or if the feature is enabled but not working, please
contact infrastructure at [email protected] or file a JIRA ticket
with INFRA.
---
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
