fix: Fix bug with structurally equal correlated subqueries#22313
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neilconway wants to merge 2 commits into
Open
fix: Fix bug with structurally equal correlated subqueries#22313neilconway wants to merge 2 commits into
neilconway wants to merge 2 commits into
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kosiew
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May 19, 2026
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@neilconway
Thanks for the fix here. I walked through the rewrite flow and the approach makes sense overall. I just had one small suggestion that could make the bookkeeping a bit more explicit and easier to reason about in the future.
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@kosiew Thanks for the review! Let me know if you have any additional feedback. |
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Which issue does this PR close?
Rationale for this change
If a query contained two or more structurally equal correlated subqueries, we previously would produce incorrect query results. This was caused by using
Subqueryas a hashmap key; if we use the subquery alias instead, we can avoid the unintended key collision. Using the alias (a string) as the hashmap key is also safer and more efficient than hashing on a complex type likeSubquery.What changes are included in this PR?
ScalarSubqueryToJoinrewrite passAre these changes tested?
Yes, with new test added.
Are there any user-facing changes?
No, aside from fixing the previously incorrect query results.