gianm commented on code in PR #5368:
URL: https://github.com/apache/calcite/pull/5368#discussion_r4418578509
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core/src/main/java/org/apache/calcite/sql2rel/RelDecorrelator.java:
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@@ -2028,8 +2027,10 @@ private static boolean isWidening(RelDataType type,
RelDataType type1) {
final RelNode oldLeft = rel.getInput(0);
final RelNode oldRight = rel.getInput(1);
- final Frame leftFrame = getInvoke(oldLeft, isCorVarDefined, rel,
parentPropagatesNullValues);
- final Frame rightFrame = getInvoke(oldRight, isCorVarDefined, rel,
parentPropagatesNullValues);
+ final Frame leftFrame =
Review Comment:
Added a comment explaining why the flags are set:
```
// Decorrelate recursively. Setting parentPropagatesNullValues lets a
scalar aggregate return
// no row for a corVar value, rather than a row of NULLs. That is safe
only for the side of a
// LEFT or RIGHT join that generates NULL values, since the join then
supplies those NULLs.
// FULL does not qualify, because it must output the aggregate's row
even when it has no match.
```
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