[thelist] mysql - selecting based on count of key

Keith Gaughan keith at digital-crew.com
Mon May 9 16:54:15 CDT 2005

David Siedband wrote:
> I have an index table that linkes to Projects and Documents based on
> foreign keys: ProjID , DocID, and I want to find documents that are
> linked to more than a threshold number of projects.
> trying some vartions on this...
>    select distinct ProjID
>    from ProjectDocuments
>    where Count(DocID) > '3'
> Can this be done in a single query?

You need to do a GROUP BY on ProjID.

More information about the thelist mailing list