It's not your English that is confusing me, it's your perl :-). You are getting your $dbh's and $sth's mixed up -- you need to name them differently, so for example $m_dbh is your MySQL dbh and $a_dbh is your AnyData dbh. But I also still don't understand what your goal is. You want to get everything in the CSV file that has a PAT equal to a PAT in the MySQL database, right? Then what do you want to do with that data?