Find and Replace String in CSV must run as Batch File

I need a script that can search through a whole csv using wildcard %% and replace that whole column with another word. The target CSV will contain up-to 150,000 entries and the source file being used to replace with will contain 50,000 entries. You may use any scripting language but must run on Windows and can be initiated from a batch file to automate the process. And you can use MySQL if you want. But please note this has to be very fast as currently i have been using the following query in MYSQL with big performance problems: UPDATE TABLE SET location = 'Leeds' WHERE location LIKE '%Leeds%'; Due to Mysql running a full table scan for each like statement and with 30,000+ this takes forever! PLEASE ONLY BID IF YOU CAN GET THIS SETUP WITHIN ONE DAY.