Treterpeter

Thanks, will try that.

Hi guys, Say I got two tables, Table1 - columns A, B, C, flag - approx 200 000 rows Table2 - columns A, B, C - approx 20 000 rows What I want to do is: Update Table1 Set flag = 1 Where "at least one row from Table2 has the same entries in columns A, B and C" Right now I am solving this with a "select distinct A, B, C from Table2" and transform this into a long where condition (with php). afterwards I apply the above update with this where condition. However this aproche needs about 5 minutes to run and I believe this could be much faster when I just know the right MySql command for this. Can anyone help me? cheers, Peter