Re: Poor Query

From: Pallav Kalva <pkalva(at)deg(dot)cc>
To: Pierre-Frédéric Caillaud <lists(at)boutiquenumerique(dot)com>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: Poor Query
Date: 2004-12-06 20:44:04
Message-ID: 41B4C494.5090304@deg.cc
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Pierre-Frédéric Caillaud wrote:

>
> Your suffering comes from the "where ba.bankaccountID =
> u.bankaccountID" in the subselect. It means postgres has to run the
> subselect once for each row in Users. You want the subselect to run
> only once, and return one (or more?) bankaccountid's, then fetch the
> users from Users.
>
> Just remove the "where ba.bankaccountID = u.bankaccountID" !
>
>> select userID, fname, lname, email, phone, dateEntered, dateCanceled,
>> dateSuspended, billAmount, billDate, dateBilled, datePaid, '?' as
>> searches
>> from Users u
>> where bankaccountid in (select bankaccountid
>> from bankaccount ba
>> where ba.bankaccountID = u.bankaccountID
>> and ba.accountnumber = '12345678'
>> and ba.routingNumber = '12345678')
>> order by UserID desc
>> limit 500
>
>
> New version :
>
> select userID, fname, lname, email, phone, dateEntered, dateCanceled,
> dateSuspended, billAmount, billDate, dateBilled, datePaid, '?' as
> searches
> from Users u
> where bankaccountid in (select bankaccountid
> from bankaccount ba
> WHERE ba.accountnumber = '12345678'
> and ba.routingNumber = '12345678')
>
> You could also do this :
>
> select u.* from Users u, bankaccount ba
> where u.bankaccountid = ba.bankaccountid
> and ba.accountnumber = '12345678'
> and ba.routingNumber = '12345678')
>
>
>
Thanks! a lot that was it , it is way much better now.

In response to

  • Re: Poor Query at 2004-12-06 20:18:28 from Pierre-Frédéric Caillaud

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