Re: Is there better SQL statement than this ?

Me again,

Thinking about my previous post, before you start looking at indexes you need to determine a number of factors and your tuning goals. The cardinality of the data, the amount of data within the tables and how often you'll be inserting, updating and deleting information from the tables. I'd also consider determining what is an acceptable reponse time for the query and aim to tune for that. i.e. you might improve performance on the select query but degrade the performance on inserts and updates due to additional I/O load by adding indexes.

Cheers
Allan

"Park Yeon Jo" <kudos12_at_netian.com> wrote in message news:d7fe264d.0301270442.7e9fa9bd_at_posting.google.com...
> It takes too long time to execute the following SQL statement ?
>
> Is there better SQL statement than this ?
>
> I didn't make any Indexes on two tables yet.
>
> Please give me the hints.
>
>
>
>
> ==================================================================
> select pmc.oid from productModelParam pmp, productModelCategory
pmc
> where pmc.oid = pmp.oid
> and pmc.categoryValue = '3E965F2E-F64E-9ECE-1B3872409AC42428'
> and pmp.paramValue = 'TH'
>
> intersect
>
> select pmc.oid from productModelParam pmp, productModelCategory pmc
> where pmc.oid = pmp.oid
> and pmc.categoryValue = '3E965F2E-F64E-9ECE-1B3872409AC42428'
> and pmp.paramValue = '50Vdc'
>
> intersect
>
> select pmc.oid from productModelParam pmp, productModelCategory pmc
> where pmc.oid = pmp.oid
> and pmc.categoryValue = '3E965F2E-F64E-9ECE-1B3872409AC42428'
> and pmp.paramValue = '0603'
Received on Mon Jan 27 2003 - 07:04:54 CST