[LucaCappelletti94]

In SQLite the comma between tables is a join operator, and every join operator may be followed by a join constraint (https://www.sqlite.org/syntax/join-clause.html). SQLite 3.51.1 runs SELECT * FROM t, u ON t.a = u.a, SELECT * FROM t, u USING (a) and chains such as t, u ON ..., v ON ..., while PostgreSQL 16 and DuckDB 1.4.4 reject all of them. The SQLite dialect failed with Expected: end of statement, found: ON.

A new dialect method, supports_comma_join_constraint, is enabled for SQLite and the generic dialect. When the table after a comma is followed by ON or USING, the FROM list parser turns it into a JOIN of the previous table and keeps parsing joins after it. Each table is parsed once, so nested derived tables stay linear. Tests cover SELECT and UPDATE ... FROM forms in SQLite and the generic dialect, and the exact error in every other dialect.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 81.33%. Comparing base (ada8314) to head (2b781e4).
⚠️ Report is 5 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2667      +/-   ##
==========================================
+ Coverage   81.28%   81.33%   +0.05%     
==========================================
  Files          42       42              
  Lines       33920    34009      +89     
  Branches    33920    34009      +89     
==========================================
+ Hits        27571    27661      +90     
+ Misses       2785     2784       -1     
  Partials     3564     3564              

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