Access 2007 form count issue

[fspata]

Hello everyone!
Pretty new to Access so bare with me lol! I've got a combo box linked to a table called Group. Their are different group areas in the table which are chosen via the drop down. I need to be able to increment a field that I'll call ABC by 1 each time the same group is chosen and the value of how many of that group is then displayed in the ABC field. Also as they checkout, they need to be subtracted from the field. Suggestions are greatly appreciated. Thanks in advance!

[June7]

Aggregate data should be calculated based on raw data records, not saved into table.

[fspata]

Aggregate data should be calculated based on raw data records, not saved into table.

Like I stated, I'm pretty new to Access and thank you for your input. What I'm looking for is just to change the number by either +1 or -1 as people come and go and display it in the ABC field. What would you suggest?

[June7]

Conventional approach would be to enter transaction records to document the increase or decrease and then run queries that calculate the net. Without knowing more about your db structure and business processes, hard to advise on specifics.

Really need to understand relational database principles and Access functionality. Have you completed any tutorials?