On Sat, 06 Nov 2010 11:59:48 -0400, Tom Lane wrote about Re: Interesting Query Performance Question: >In general, NOT IN is hard to optimize because of its weird behavior >for NULLs. I'd suggest looking into converting the query to use an >EXISTS instead. I have know about that issue for some years, so I always use a column that has been declared NOT NULL for the sub-query. Does PostgreSQL not use that property to bypass the vagaries of NULL in an IN predicate? -- Regards, Dave [RLU #314465] *-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-* dwnoon@xxxxxxxxxxxx (David W Noon) *-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
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