The NULL in your NOT IN

This site does not allow itself to be embedded. You can still read it on the original site — the toolbar below keeps your place in the directory.

A NOT IN query can return the wrong answer without telling you. It is valid SQL, it runs without an error, and it hands back a perfectly well-formed result set that happens to be empty when it should not be. No warning, no hint, nothing in the logs: just zero rows where you expected hundreds, and a database that considers it correct. Almost always the cause is a single NULL sitting somewhere you…

Read on boringsql.com ↗