Re: IN vs EXISTS equivalence

On Aug 8, 2008, at 3:23 PM, Tom Lane wrote:
> * has no set operations (UNION etc), grouping, set-returning functions
> in the SELECT list, LIMIT, or a few other funny cases


Couldn't union/union all be treated as

EXISTS(a)
OR EXISTS(b)
...

Or am I missing some detail with NULLS?

Personally, I'd rather write it as separate EXISTS clauses rather  
than using UNION, but perhaps others have a different preference...
-- 
Decibel!, aka Jim C. Nasby, Database Architect  decibel@decibel.org
Give your computer some brain candy! www.distributed.net Team #1828