On 8 Apr 2002, at 18:18, Ari B Kahn wrote: > OK. Now notice that insFreq has DOUBLED when used in conjunction with > with delFreq! > mysql> select t1.andersonStart_pos, sum(t2.insFreq), sum(t1.delFreq) > from InsertionFreq t2, DeletionFreq t1 where (t2.andersonStart_pos = > 1072) and (t1.andersonStart_pos = 1072) group by t1.andersonStart_pos; > +-------------------+-----------------+-----------------+ > | andersonStart_pos | sum(t2.insFreq) | sum(t1.delFreq) | > +-------------------+-----------------+-----------------+ > | 1072 | 190 | 73 | > +-------------------+-----------------+-----------------+ > > Is this a known bug? I couldn't find anything. Or is it just my SQL?
It's your SQL. You're not specifying any criterion for joining the tables, so your result set will contain every possible combination of a row from InsertionFreq that has andersonStart_pos = 1072 and a row from DeletionFreq that has andersonStart_pos = 1072. That means if there are 2 rows like that in DeletionFreq your insFreq sum will be twice what you expected. If there's a relationship between the rows in the two tables, then use it to specify a join criterion. If there's not, then leave it as two queries the way you did first. -- Keith C. Ivey <[EMAIL PROTECTED]> Tobacco Documents Online http://tobaccodocuments.org --------------------------------------------------------------------- Before posting, please check: http://www.mysql.com/manual.php (the manual) http://lists.mysql.com/ (the list archive) To request this thread, e-mail <[EMAIL PROTECTED]> To unsubscribe, e-mail <[EMAIL PROTECTED]> Trouble unsubscribing? Try: http://lists.mysql.com/php/unsubscribe.php
