adriangb opened a new pull request, #17520: URL: https://github.com/apache/datafusion/pull/17520
## Summary - Fixes #17513 - Fixes regression introduced by #17295 where `SELECT FROM table WHERE condition` incorrectly returned all columns instead of empty projection ## Problem PR #17295 added support for FROM-first syntax (e.g., `FROM table` without SELECT). However, it couldn't distinguish between: - `FROM table` - should select all columns (FROM-first syntax) - `SELECT FROM table WHERE ...` - should select no columns (empty projection) Both cases resulted in empty projection lists in the parser, making them indistinguishable. ## Solution The fix checks for the presence of a WHERE clause to differentiate: - Empty projection + no WHERE clause = FROM-first syntax → add wildcard projection - Empty projection + WHERE clause = SELECT FROM syntax → keep empty projection This ensures: - `FROM table` returns all columns (expected FROM-first behavior) - `SELECT FROM table WHERE condition` returns empty columns but correct row count - The optimizer still pushes down column requirements to TableScan for efficiency ## Test Changes Updated the test expectation in `projection.slt` to correctly show that `SELECT FROM table WHERE ...` produces an empty Projection node in the logical plan, while the TableScan still only projects the necessary columns. 🤖 Generated with [Claude Code](https://claude.ai/code) Co-Authored-By: Claude <nore...@anthropic.com> -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: github-unsubscr...@datafusion.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: github-unsubscr...@datafusion.apache.org For additional commands, e-mail: github-h...@datafusion.apache.org
