You're not far off, BrowserUK and mahi's answers to your Q sounds good. I'd like to try to give you an answer but have to ask a Q of my own, -do you have what would be a master DB against which you would compare all others ? Or do you simply wish to find the differences between them and then merge all ? Another Q, if you have differences, what would you like to do with the different data fields, dump them, store them, or intergrate them ??? Or maybe you've already figured this out!