[CALCITE-7688] Support scalar subqueries in table function arguments

[tkalkirill]

Jira Link

CALCITE-7688

Changes Proposed

This PR introduces support for scalar subqueries and expressions containing scalar subqueries in table function arguments:

SELECT * FROM TABLE(my_function((SELECT value FROM t), 1));

SELECT * FROM TABLE(my_function((SELECT 4) + (SELECT 6), 1));

SELECT *
FROM person p
CROSS JOIN LATERAL TABLE(
  my_function((SELECT p.id + 1), p.id)
);

[mihaibudiu]

the commit message is not ideal.
Is this work in progress, or is it ready for review?

[tkalkirill]

@mihaibudiu It's a habit from the IGNITE project, where they don't pay as much attention to commit messages. It's ready for review, could you take a look?

[mihaibudiu]

I will review, but to merge this you will have to use the same commit message as the JIRA issue title.

[mihaibudiu]

I am not sure that the interpreter module is being actively maintained or complete. Some of the changes in this PR seem not directly related to the actual JIRA issue 7688. The SubQueryRemoveRule is what should be the focus of this PR.

If you want to bring the interpreter up-to-date, please check for JIRA issues related to that or file new ones and submit that part of the work as separate PRs.

[mihaibudiu]

This generally looks fine

[mihaibudiu]

I hope that you have validated these results in some way.
Maybe you can say how.
Ideally you wrote a test oracle (a separate program) which verified these results.

[tkalkirill]

I validated the expected results independently against Oracle using a standalone PL/SQL test oracle https://onecompiler.com/plsql/44xe3ubj8. The program defines a pipelined table function and invokes it with the same scalar subquery, literal, and correlated outer-column arguments. Oracle produced (100, 10, 20, 100) and (200, 10, 20, 200), which matches the test expectations.
Or did you mean something else?

[mihaibudiu]

I wonder why this file is named Smalls.java.

[tkalkirill]

Smalls like teen spirit.

[mihaibudiu]

Please squash the commits for merging

[tkalkirill]

@mihaibudiu Done.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
94.5% Coverage on New Code
0.0% Duplication on New Code

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