That helped tremendously - it's been so many years since I last tried my hand at database work I had completely forgotten about the uses of the union clause. Thanks for all your help!

Sorry, in my attempt to simplify things to make it easier to understand, I actually made it more difficult. Here's a little more info on the problem:

data1 is various hypothetical values gathered from different places. data2 is the actual measured value. So while I could merge these two tables and either have a column like "isActual" or just set the site field to -1 to indicate that this value is the actual value, that...

Hey all - just found this site and I am hoping you can help me with a problem I am having constructing a query for a MS Access 2007 database. I have 3 tables of data simplified as follows
- persons: personID, name
- data1: personID, week, year, place, value
- data2: personID, week, year, value

The persons table is required, but, for a given week and year, the person can have data in either data1, data2, or both....