Question

I’m using Access to fill in details in a database across 3 offline computers. This means they all have a copy of the database, do a day of info filling, then get manually uploaded to a central database. Horrid, but it’s the only option.

I have a pre-filled database, key identifiers etc are all determined previously; we are adding information to the blank fields for these entries. (Started with 3 key fields, added a few info fields). The user selects an entry and edits it rather than creating one. I then use a script which takes each table and unions the three databases into a table for each. The users do not duplicate work (meaning you don’t have Jack working on entry A as well as Jill working on entry A).

My question: How can I get my union query to select all entries, even the unfilled ones, but let the filled ones take precedence? (aka bypass the “duplicate entry” error by choosing the filled in entry instead of the two unfilled entries?)

ex:

JOHN's DB            JACK's DB              JILL's DB      --->      MASTER DB
A: 1, 1, __          1, 1, __              1, 1, "Yes"              1, 1, "Yes"
B: 1, 2, "No"        1, 2, __              1, 2, __                 1, 2, "No"
C: 1, 3, __          1, 3, __              1, 3, "No"               1, 3, "No"

Completely terrible way to do this (Unioning offline tables, that is) but we have little other choice due to many other uncontrollable factors.

Answer 1

How about

 SELECT Id, Max(Field) 
 FROM ( Select Id, Field FROM John
        Union All ...)
 GROUP BY Id