Jack Chen created SPARK-44551:
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Summary: Wrong semantics for null IN (empty list) - IN expression
execution
Key: SPARK-44551
URL: https://issues.apache.org/jira/browse/SPARK-44551
Project: Spark
Issue Type: Sub-task
Components: SQL
Affects Versions: 3.4.0
Reporter: Jack Chen
{{null IN (empty list)}} incorrectly evaluates to null, when it should evaluate
to false. (The reason it should be false is because a IN (b1, b2) is defined as
a = b1 OR a = b2, and an empty IN list is treated as an empty OR which is
false. This is specified by ANSI SQL.)
Many places in Spark execution (In, InSet, InSubquery) and optimization
(OptimizeIn, NullPropagation) implemented this wrong behavior. Also note that
the Spark behavior for the null IN (empty list) is inconsistent in some places
- literal IN lists generally return null (incorrect), while IN/NOT IN
subqueries mostly return false/true, respectively (correct) in this case.
This is a longstanding correctness issue which has existed since null support
for IN expressions was first added to Spark.
Doc with more details:
[https://docs.google.com/document/d/1k8AY8oyT-GI04SnP7eXttPDnDj-Ek-c3luF2zL6DPNU/edit]
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