planner: make var_samp can be used as a window function (#53130)

[ti-chi-bot]

This is an automated cherry-pick of #53130

What problem does this PR solve?

Issue Number: close #52933

Problem Summary:

What changed and how does it work?

From the MySQL plan:

mysql> explain analyze select var_samp(c1) over (partition by c1) from t1;
+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| EXPLAIN                                                                                                                                                                                                                                                                                                                |
+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| -> Window aggregate with buffering: var_samp(t1.c1) OVER (PARTITION BY t1.c1 )   (cost=0 rows=1) (actual time=0.139..0.139 rows=0 loops=1)
    -> Sort: t1.c1  (cost=0.35 rows=1) (actual time=0.133..0.133 rows=0 loops=1)
        -> Table scan on t1  (cost=0.35 rows=1) (actual time=0.116..0.116 rows=0 loops=1)
 |
+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.01 sec)

• Made var_samp can be used as a window function.
• Added a test case for use var_samp as window function cause unexpected error #52933.

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)
• No need to test

  • I checked and no code files have been changed.

Side effects

• Performance regression: Consumes more CPU
• Performance regression: Consumes more Memory
• Breaking backward compatibility

Documentation

• Affects user behaviors
• Contains syntax changes
• Contains variable changes
• Contains experimental features
• Changes MySQL compatibility

Release note

Please refer to Release Notes Language Style Guide to write a quality release note.

Make `var_samp` can be used as a window function.
使 `var_samp` 可以用作窗口函数。

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

❗ No coverage uploaded for pull request base (release-8.1@d774c73). Click here to learn what that means.

Additional details and impacted files

@@               Coverage Diff                @@
##             release-8.1     #53288   +/-   ##
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  Coverage               ?   71.1541%           
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  Lines                  ?     421221           
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  Hits                   ?     299716           
  Misses                 ?     101029           
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Flag	Coverage Δ
unit	71.1541% <100.0000%> (?)

Flags with carried forward coverage won't be shown. Click here to find out more.

Components	Coverage Δ
dumpling	53.9957% <0.0000%> (?)
parser	∅ <0.0000%> (?)
br	40.9772% <0.0000%> (?)

[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2024-05-16 02:50:16.3369851 +0000 UTC m=+1707970.094120674: ☑️ agreed by hi-rustin.
• 2024-05-16 02:51:13.40417011 +0000 UTC m=+1708027.161305681: ☑️ agreed by tangenta.

[tangenta]

/approve

[easonn7]

/approve

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: easonn7, hawkingrei, hi-rustin, tangenta

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