SQL

UPDATE vare  SET beholdning = beholdning -1

That is for ALL vare, for a specific then use

UPDATE vare  SET beholdning = beholdning -1 WHERE vareNumber = someNumber

If you make a query in the query builder you could use

UPDATE vare  SET beholdning = beholdning -1 WHERE vareNumber = [Indast Vare nummer]

and Access will ask you to enter a number
NOTE: You need to change vareNumber to the CORRECT name

Mange tak, det virker bare :-)

tak :o)