Trying to synchronize the rows in two tables...

[Jim Brunk]

I'm trying to synchronize the rows in two tables where 'code' is in a unique index (I've checked for duplicates). I can run:

SELECT table1.code
FROM table1 LEFT JOIN table2 ON table1.code = table2.code
WHERE table2.code IS NULL

But when I try to run the reverse:

SELECT table2.code
FROM table2 LEFT JOIN table1 ON table2.code = table1.code
WHERE table1.code IS NULL

nothing ever happens... no returned values, no error messages, nothing.

I was using MySQL version 5.0.45 on Mac OS X Server 10.5.8 when I first experienced the problem. I have now upgraded to MySQL version 5.1.55 and mysql_upgrade shows everything OK, but the problem still exists. Both directions work for some tables, but not for others.

Anybody know why the second statement won't work?