infoschema: set TABLES.TABLE_COLLATION null

[hawkingrei]

Signed-off-by: Weizhen Wang wangweizhen@pingcap.com

What problem does this PR solve?

Issue Number: close #27970

Problem Summary:

What is changed and how it works?

What's Changed:

when table_type is VIEW, TABLES.TABLE_COLLATION will be null. but TABLE_COLLATION is defined as NUT NULL. so fold IsNull function to constant true / false if the expression is marked as NotNull. it will return wrong result.

How it Works:

set TABLES.TABLE_COLLATION null.

Check List

Tests

• Unit test

Release note

None

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• AilinKid
• zimulala

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[hawkingrei]

/run-check_dev_2

[zimulala]

LGTM

[zimulala]

/merge

[ti-chi-bot]

This pull request has been accepted and is ready to merge.

Commit hash: 5e6e5fa

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