barney wrote:
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
Well, that's what happens when you don't include relevant information, such as your table definitions, in your question.
No, you don't need to modify your tables. You just need to use the join syntax that fits your situation. USING works when the join column has the same name in each table. Otherwise, you need to use ON. Hence, you need something like
SELECT FileKey FROM dl_files LEFT JOIN dl_merges ON dl_files.ID = dl_merges.FileID WHERE FileID IS NULL; See the manual for details <http://dev.mysql.com/doc/refman/4.1/en/join.html>. Michael -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
