cloud-fan commented on code in PR #40865: URL: https://github.com/apache/spark/pull/40865#discussion_r1177426150
########## sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/subquery.scala: ########## @@ -459,7 +459,7 @@ object RewriteCorrelatedScalarSubquery extends Rule[LogicalPlan] with AliasHelpe case alias @ Alias(_: AttributeReference, _) => (alias.exprId, Literal.create(null, alias.dataType)) case alias @ Alias(l: Literal, _) => - (alias.exprId, l.copy(value = null)) + (alias.exprId, l) Review Comment: I think this one-line change is all we need. Count bug does not apply to the count function only, but all expressions in Aggregate that return non-null value for empty input. This includes all constant values. Assume there are two table `t1(c1 int)`, `t2(c2 int)`. `t2` has two rows (1, 2), `t3` has two rows (1,3) ``` scala> sql("select (select f from (select false as f, max(c1) from t1 where c1 = c2)) from t2").show +------------------+ |scalarsubquery(c2)| +------------------+ | false| | NULL| +------------------+ ``` The result is wrong and it should be false, false ########## sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/subquery.scala: ########## @@ -459,7 +459,7 @@ object RewriteCorrelatedScalarSubquery extends Rule[LogicalPlan] with AliasHelpe case alias @ Alias(_: AttributeReference, _) => (alias.exprId, Literal.create(null, alias.dataType)) case alias @ Alias(l: Literal, _) => - (alias.exprId, l.copy(value = null)) + (alias.exprId, l) Review Comment: cc @jchen5 -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: reviews-unsubscr...@spark.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: reviews-unsubscr...@spark.apache.org For additional commands, e-mail: reviews-h...@spark.apache.org