Implement SHOW INDEX

[rschu1ze]

Fixes #49140

The implementation is modeled after MySQL's SHOW INDEX. This leads to some weird naming and a few unused fields ...

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• New Feature

Changelog entry (a user-readable short description of the changes that goes to CHANGELOG.md):

Support statement SHOW INDEX to improve compatibility with MySQL

[alexey-milovidov]

SQL injection.

[rschu1ze]

I tried a few injection attacks from here but either the parser rejected such queries or there was an error when the rewritten query was executed.

What worked was an attack with 1=1, e.g. show columns from tbl where field = 'b' or 1=1. Since we would still be limited to system tables and not expose arbitrary table data, that should be okay as behavior.

[alexey-milovidov]

Just put into backQuoteIfNeed

[robot-ch-test-poll3]

This is an automated comment for commit f7e31a9 with description of existing statuses. It's updated for the latest CI running
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[alexey-milovidov]

SQL injection.

[alexey-milovidov]

Add a test with the database name and table name containing the ' character.

[rschu1ze]

The parsers of SHOW INDEX and SHOW COLUMNS expect database and table as identifiers, whereas WHERE table/database = expects a string literal. The mismatch is now properly resolved using quoting. I have also added a test.

[alexey-milovidov]

Ok. There are also manipulators escape and quote in Operators.h

[rschu1ze]

Ok. There are also manipulators escape and quote in Operators.h

Sure, I just found it more readable to write the generated SELECT query using with as little abstractions as possible.

[alexey-milovidov]

Ok. While the safest way is AST construction.

[rschu1ze]

Test failures also occur in master --> merging