Oh, I see. I shouldn't have mentioned that because it was confusing. I just meant that I don't know how the broker team determines which client is the...

Which part of the business logic don't you understand? I thought that I explained a lot of detail there and spelled out the query's goal explicitly.

OK. I figured that if I got the min(postdate) for each client set then I could compare the min(postdate) to Jan. 1, 2011 and only include the new ones....

A new client is one whose very first non-zero transaction occurred (posted) sometime this year. However, the first transaction could come from any member of a client set, meaning...

Sorry about that. I should have been more clear. The SQL I posted was just my first attempt at starting to figure the whole problem out. I...