Search all clients

Hi,

I need to be able to do a search the shows me all clients that do not have a certain product sold to them. The products are in different tables so need to search all the tables.

I assume I would search something like:

where clientid=null in product1table?

what i was wondering is if i should or could use dataassist or any other extension for this or should i just use a custom page? I basically want to have a drop down box 2.

in the first drop down box it would say "sold" or "not sold". then the second drop down list would have a list of all products: "product1", "product2" etc

i need to be able to allow the user to click on the first drop down which determines what search to use, either if the table has the clientid in it or null. then return the results on the page.

hope someone can help me with this one.

thanks