'Add' records

[elamberton]

I have a query that imports one table into another. It duplicates the records from time to time but without any reason. What are some of the reasons why it could be doing this and can I get by without writting a query to find and delete the duplicates?

 

[DaniBoy]

Hello,
If I append one table's field to the primary key of another table with data on it already and no duplicates, it should just update the the new information right? it will not duplicated? right?
Let me know