MySQL Database Compare and overwrite

Hi All, I have a mysql database and require someone to compare it to an older CSV File and update the DB with the values in one field and overwrite the db with the content from the CSV File. Example: MySQL Columns LAST NAME | COMPANY | ZIP CODE | SOURCE CSV Columnss LAST NAME | COMPANY | ZIP CODE | SOURCE If the records match last LAST NAME, COMPANY AND ZIP CODE then take the value in SOURCE from the CSV File and dump it in the source file overwriting whatever was there. If anything is unclear please let me know.