In query: check criteria with default value

[hoachen]

I am not sure how to accomplish this and need all of your expertise and guide me! Thanks!

Table1
Combined key: smimark (first 3 letter of smith and first 4 letters of Marker)
Item#: 123456
Qty: 2
Combined key: MarJaso (first 3 letter of Mary and first 4 letters of Jason)


Item#: 44587
Qty: 5

Combined key: MarJaso (first 3 letter of Mary and first 4 letters of Jason)
Item#: 336363
Qty: 3
In the query I would like to be able to check to the combined key. If the combined key not the same put a default value of -99. If there are same combined key then I would like it decease the default value on second record to -98 and so forth (-97) if there are more same combined key.
Currently,I can put only the default value of -99 by Field: Exp1: val(-99).
Is there a way to do it?
Thanks

[TheShabz]

I think you got the carriage before the horse here. Your combined keys are not unique. That defeats the purpose of a key. What exactly are you trying to accomplish by putting those values in?