Github user yhuai commented on a diff in the pull request:
https://github.com/apache/spark/pull/7841#discussion_r44500328
--- Diff:
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/Analyzer.scala
---
@@ -248,6 +253,38 @@ 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))
--- End diff --
I guess the underlying assumption of this line is that aggregate function
should ignore `null` input values, right? (Basically, `null` should have no
impact on the result of this aggregate function.) If so, can we add a comment
at here?
---
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]
