Use select first_table.id from first_table left join second_table using (id) where second_table.id is null
Stefan Am Saturday 25 March 2006 19:10 schrieb barney: > Folk, > > 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 -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
