SQL JOIN or EXISTS? Chances Are, You’re Doing it Wrong

I've noticed this very consistently with a lot of customers, and also with participants of our Data Geekery SQL Workshop (which I highly recommend to everyone, if you excuse the advertising): A lot of developers get the distinction between JOIN and SEMI-JOIN wrong. Let me explain... What are JOIN and SEMI-JOIN A little bit of … Continue reading SQL JOIN or EXISTS? Chances Are, You’re Doing it Wrong

The truth about IN and EXISTS in SQL

Very nice article, finally getting rid of some doubts... (at least for Oracle) http://explainextended.com/2009/09/30/in-vs-join-vs-exists-oracle/