Thanks, Stefan, But that only works if both tables have the same field name, doesn't it? If I use select FileKey from dl_files left join dl_merges using (FileID) where FileID is null MySQL returns Unknown column 'articles.dl_files.FileID' in 'on clause'.
Correct me if I'm wrong, but wouldn't I have to modify the column name in one of the tables in order for that to work? Or is there a syntax in the join lexicon that I can use to alias one of the column names within the query? I can't modify the existing table structure(s). Apologies if I'm being dense. Make a good day ... ... barn > 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] -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]