Subtract one table from another?

[ya5irha55an]

Hi, I hope someone can help me out with this problem:

I have 2 tables with identical stucture, and no unique ID number.
Both had identical data, and the databse was then copied onto 2 laptops. Now further data was added onto each.

I want to now merge the three databses (ie original one, and 2 laptops) into 1, without creating duplicates- so I need to identify which are the new fields added to the databases. I figured that by somehow subtracting the original table from the new ones, i would be left with the new data, but dont know how to do this. Or is their another way?

 

[Pat Hartman]

What would uniquely identify each record? Make a new table with a multi-field primary key. Add the original data. Then append each subsequent file. Duplicates will be discarded.

 

[Keith Nichols]

hi Ya,

Use an Find Unmatched Items query.

Select queries in the database objects panel, New/Find Unmatched Items. The wizard is fairly straightforward.

You need to create 2 queries, 1 for unmatched items in table A from table B and another the other way round.

I think the subtract one table from another is possible using Union Queries but what you want to do is probably easier done as described.

HTH.