[Forums] SQL WHERE NOT IN

Hi,

https://www.red-gate.com/hub/product-learning/sql-prompt/consider-using-not-exists-instead-not-subquery

contains the following statement about NOT IN:

you need to be cautious when using the NOT IN operator if the subquery’s source data contains NULL values. If so, you should consider using a NOT EXISTS operator instead of NOT IN, or recast the statement as a left outer join.

Maybe this relates to your problem.

Regards,

Daniel