Re: many Union all vs. inserting results to temp table

deann15_at_yahoo.com wrote:
> I have a dynamic query which basically loop through an ID field in a
> table then build queries dynamically then union all the queries
> together, such as:
>
> select * from (complex subquery) where a = 1
> union all
> select * from (complex subquery) where a = 2
> union all
> select * from (complex subquery) where a = 3
> ...
>
> Depending on what a user select, the query could have a few thousand
> unions. My question is about scalability and performance: will it be
> better if inserting the results of every query to a global temp table
> then select * from the temptable instead of executing the long query
> all at once?

If you are going to use a temp table, why not populate it with the different values of a, then do one query joining "(complex subquery)" to the temp table?

Xho

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