[vox-tech] SQL selecting distinct from multiple index tables

Jeff Newmiller vox-tech@lists.lugod.org
Fri, 30 Jan 2004 22:04:39 -0800 (PST)


On Fri, 30 Jan 2004, Mitch Patenaude wrote:

> select distinct O.OID, O.Name, O.Acronym
>    from Organizations O, OrgDocs D, OrgProjects P
>     where D.OrgID  = O.OID or P.OrgID = O.OID
> 
> I think this will result in two full table scans though......

Actually, it will probably result in Count(P.*) passes through P... 
very inefficient.

I think you were on the right track originally ... probably dump the
results of both queries to a temporary table and retrieve distinct rows.

> 
>    -- Mitch
> 
> On Friday, Jan 30, 2004, at 21:24 US/Pacific, David Siedband wrote:
> 
> > I have two index tables the associate Organizations with documents and 
> > projects.  I'm trying to write a query that returns all the 
> > organizations that are associated with either a project or document.
> >
> > To select distinct organization that are either associated with a 
> > Document or a Project, I'm using SQL that looks like this.
> >
> > select distinct Organizations.OID , Organizations.Name , 
> > Organizations.Acronym
> > from OrgDocs , Organizations
> > where OrgDocs.OrgID = Organizations.OID
> >
> > select distinct Organizations.OID , Organizations.Name , 
> > Organizations.Acronym
> > from OrgProjects , Organizations
> > where OrgProjects.OrgID = Organizations.OID
> >
> > Any suggestions on how to combine this into a single query?
> >
> > thx,
> >
> > --
> > David
> >
> >
> >
> >
> >
> >
> > _______________________________________________
> > vox-tech mailing list
> > vox-tech@lists.lugod.org
> > http://lists.lugod.org/mailman/listinfo/vox-tech
> >
> 
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