Re: Must I use DISTINCT? - Mailing list pgsql-sql

From Stephan Szabo
Subject Re: Must I use DISTINCT?
Date
Msg-id 20090205220522.G36179@megazone.bigpanda.com
Whole thread Raw
In response to Must I use DISTINCT?  (Michael B Allen <ioplex@gmail.com>)
List pgsql-sql
On Thu, 5 Feb 2009, Michael B Allen wrote:

> Please consider the following SQL
>
>   SELECT e.eid, e.name
>   FROM entry e, access a
>   WHERE e.eid = 120
>   AND (e.ownid = 66 OR e.aid = a.aid)
>
> The intent is to match one entry with the eid of 120. However I would
> like to impose an additional constraint that either e.ownid must be 66
> or e.aid must match the aid of an entry in the access table (there's
> actually a lot more to the query but I think this should be sufficient
> to illustrate my problem).
>
> The problem is that the e.ownid is 66 and therefore the same entry is
> returned for each access entry.
>
> Of course I can simply SELECT DISTINCT but that seems like an improper
> usage of DISTINCT here.
>
> Is there an alternative way to write this query? I only want to select
> from the access table for the purpose of constraining by aid.

Would something like:SELECT e.eid, e.name FROM entry e WHERE e.eid = 120 AND(e.ownid = 66 OR e.aid in (select a.aid
fromaccess a))
 
do what you wnat?


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