If it works on your sample but not when you run it on real data then you need to find out the characteristics of the rows that do NOT work as you expect. That will tell you why it isn't working like you expect. My guess is that the fname/lname match is not hitting like you think it should. Most likely cause is padding with spaces or not, or maybe leading space(s) or possibly some non-printable characters in the data. look there first.