[3.1] Fix to #19825 - Query: incorrectly generating JOIN rather than APPLY for subqueries with outside references to a joined table #20064
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…for subqueries with outside references to a joined table During translation, when we decide whether we can apply JOIN or APPLY we visit inner SelectExpression looking for references to tables in the outer SelectExpression. Problem was that we were using Contains method, which would not match cases where the outer table was in the form of JoinExpressionBase. Fix is to use ContainsTableReference method which matches different types of tables.
maumar
changed the title
smitpatel
approved these changes
Feb 27, 2020
|
Approved by tactics for 3.1.4. Wait for branch to open before merging. |
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Description
During translation, when we decide whether we can apply JOIN or APPLY we visit inner SelectExpression looking for references to tables in the outer SelectExpression.
Problem was that we were using Contains method, which would not match cases where the outer table was in the form of JoinExpressionBase.
Fix is to use ContainsTableReference method which matches different types of tables.
Customer Impact
Invalid sql generated for relatively complicated but common query pattern. No easy workaround.
How found
Reported by multiple customers.
Test coverage
We have added test to cover this scenario.
Regression?
No.
Risk
Low. Fix is very isolated. Logic used to fix the issue is already being used in other places without problems. Quirk added.