select first_table.id from first_table left join second_table using (id) where
second_table.id is null
Am Saturday 25 March 2006 19:10 schrieb barney:
> This may be off-base for this list, but I've run out of places to look,
> sorry. I can't seem to find this anywhere, although I'm certain I've seen
> it before.
> How can I identify all the records in a table that are not referenced in a
> many-to-many table?
> I have a [unique] table of files and a [unique] table of attributes. These
> are linked in a merge table which is many-to-many. I need to find all
> items in the file table that are not referenced in the merge table in order
> to add appropriate attributes for those records. The attribute list is
> 26-30 records and the file table is currently about 3,200 records, which
> could make for a merge table of 96,000 records.
> I tried using an IN statement against a sub-select of unique file ids in
> the merge table, but either that will not work or I did not craft it
> properly The query hit 6 million records before I aborted it <sigh />.
> I'm certain this can be done ... I seem to remember a similar process from
> the DB2 corporate days ... but I just cannot wrap my head around it.
> Anybody have any ideas, please?
> Make a good day ...
> ... barn
Stefan Kuhn M. A.
Cologne University BioInformatics Center (http://www.cubic.uni-koeln.de)
Zülpicher Str. 47, 50674 Cologne
Tel: +49(0)221-470-7428 Fax: +49 (0) 221-470-7786
My public PGP key is available at http://pgp.mit.edu