03.05.2014 20:48, Leyne, Sean wrote: > > My statement was based on my memory of why the use of IS NOT NULL was > disabled in earlier FB releases. > > If IS NOT NULL can be treated the same as any other condition, why isn't it > now?
Firebird (and many other DBMS) simply don't use indices for negated conditions, I suppose this is the only reason. However, there is a big difference between COL <> 0 and COL IS NOT NULL, because NULLs are always either at the beginning or at the tail, so a range scan becomes possible. Dmitry ------------------------------------------------------------------------------ "Accelerate Dev Cycles with Automated Cross-Browser Testing - For FREE Instantly run your Selenium tests across 300+ browser/OS combos. Get unparalleled scalability from the best Selenium testing platform available. Simple to use. Nothing to install. Get started now for free." http://p.sf.net/sfu/SauceLabs Firebird-Devel mailing list, web interface at https://lists.sourceforge.net/lists/listinfo/firebird-devel
