Github user nsyca commented on a diff in the pull request:
https://github.com/apache/spark/pull/15763#discussion_r86603248
--- Diff:
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/Analyzer.scala
---
@@ -1044,6 +1044,34 @@ class Analyzer(
failOnOuterReference(p)
p
}
+
+ // SPARK-17348
+ // Looking for a potential incorrect result case.
+ // When a correlated predicate is a non-equality predicate
+ // it must be placed at the immediate child operator.
+ // Otherwise, the pull up of the correlated predicate
+ // will generate a plan with a different semantics
+ // which could return incorrect result.
+ var continue : Boolean = true
--- End diff --
That scenario above is banned with this PR (and added as a new, negative,
test case). However, the PR has a greater scope, Window function is another
operator, we cannot pull up any correlated predicates, such as the example
below:
// Case 2: window func
Seq((2,1)).toDF("c1","c2").createOrReplaceTempView("t1")
Seq((1,1),(2,2)).toDF("c1","c2").createOrReplaceTempView("t2")
sql("select c1 from t1 where c1 in (select max(t2.c1) over () from t2
where t1.c2 >= t2.c2)").show
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