From: | Stephan Szabo <sszabo(at)megazone(dot)bigpanda(dot)com> |
---|---|
To: | Michael B Allen <ioplex(at)gmail(dot)com> |
Cc: | pgsql-sql(at)postgresql(dot)org |
Subject: | Re: Must I use DISTINCT? |
Date: | 2009-02-06 06:11:39 |
Message-ID: | 20090205220522.G36179@megazone.bigpanda.com |
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Thread: | |
Lists: | 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 from access a))
do what you wnat?
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