Re: subquery in case expression
Posted in 2006
Art S. Kagel — — source: Usenet: comp.databases.informix
bozon wrote: > Sometimes I wish I could take a post back. I started thinking about it > and I realized that you were using "union all" to run all of the > seperate queries in parallel (assuming PDQ is on). This is a nice trick > that I hadn't thought of before. Regular unions can't really do this > because they each kind of depend on the others, in your query you just > need to make sure each clause is disjoint from the other. This is a > very nice trick. No problem. BTW, I think that a normal UNION (don't get us started on which type of UNION is 'normal' again) can be parallelized also. The results just have to be gathered at the end for a unique filtered sort. Art S. Kagel <SNIP>