[slfan1989]

Purpose

Linked issue: closes #1269

Fix MERGE statements failing with aliases containing spaces, reserved words, embedded quotes, or case-sensitive names.

Brief change log

• Preserve aliases as sqlparser Ident values throughout MERGE execution.
• Retain quoting, escaping, and case when generating SQL and rewriting column qualifiers.
• Add regression coverage for table and subquery aliases on ordinary and Data Evolution tables.

Tests

• Confirmed both new regression tests fail before the fix.

API and Format

No.

Documentation

No.

[slfan1989]

Hi @JingsongLi, @QuakeWang Could you please review this PR when you have time? It fixes quoted alias handling in MERGE statements and adds regression tests. Thanks!

[QuakeWang]

Non-blocking: could we retain Ident here and compare aliases using DataFusion’s identifier rules? The downstream eq_ignore_ascii_case conflates target "T" with source "t", treating "t".value = "t".value as a target/source partition equality. I reproduced this on a partitioned CoW table: pruning skips a matching target row, and MERGE inserts instead of updating it. It would be good to handle this here and add a regression test.

[slfan1989]

Thanks for the review! I’ll preserve Ident in the partition-pruning checks, follow DataFusion’s identifier rules, and add a regression test for case-sensitive aliases.