> > That's a common technique with LEFT JOIN > > Thanks, Igor. >
A bit MySQL specific, but shows some options http://explainextended.com/2010/05/27/left-join-is-null-vs-not-in-vs-not-exists-nullable-columns/ Regards Andy Ling --------------------------------------------------------------------------------------- This email has been scanned for email related threats and delivered safely by Mimecast. For more information please visit http://www.mimecast.com ---------------------------------------------------------------------------------------
