Feature: Multi Target Update Support

[harshit-gangal]

Description

This PR is an enhancement on earlier PR to add support for multi-target update.

Example: update user u join m on u.col = m.col set u.foo = 32, m.bar = 23 where u.id = 2
The SQL here updates columns from two tables using the join condition.

Related Issue(s)

• Add support for Update Multi Table #15211

Checklist

• Tests were added or are not required
• Did the new or modified tests pass consistently locally and on CI?
• Documentation was added or is not required

Deployment Notes

[vitess-bot]

Review Checklist

Hello reviewers! 👋 Please follow this checklist when reviewing this Pull Request.

General

• Ensure that the Pull Request has a descriptive title.
• Ensure there is a link to an issue (except for internal cleanup and flaky test fixes), new features should have an RFC that documents use cases and test cases.

Tests

• Bug fixes should have at least one unit or end-to-end test, enhancement and new features should have a sufficient number of tests.

Documentation

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• There should be some code comments as to why things are implemented the way they are.
• There should be a comment at the top of each new or modified test to explain what the test does.

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Backward compatibility

• Protobuf changes should be wire-compatible.
• Changes to _vt tables and RPCs need to be backward compatible.
• RPC changes should be compatible with vitess-operator
• If a flag is removed, then it should also be removed from vitess-operator and arewefastyet, if used there.
• vtctl command output order should be stable and awk-able.

[codecov]

Codecov Report

Attention: Patch coverage is 92.67016% with 14 lines in your changes are missing coverage. Please review.

Project coverage is 65.64%. Comparing base (983a3c8) to head (20b3b5f).
Report is 3 commits behind head on main.

Files	Patch %	Lines
go/vt/vtgate/planbuilder/operators/update.go	94.61%	7 Missing ⚠️
go/vt/vtgate/semantics/semantic_state.go	77.77%	4 Missing ⚠️
go/vt/vtgate/planbuilder/operators/delete.go	89.47%	2 Missing ⚠️
go/vt/vtgate/planbuilder/operators/dml_planning.go	87.50%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #15402      +/-   ##
==========================================
- Coverage   65.72%   65.64%   -0.08%     
==========================================
  Files        1562     1562              
  Lines      193952   194318     +366     
==========================================
+ Hits       127474   127567      +93     
- Misses      66478    66751     +273     

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