Keep track of stock items by query

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Hy, I have this db where a user can purchase and item and total stock number needs to be updated.

I can calculate how many items are left but how to update the warehause table?

I can live without table updating, but if the same item is purchased multiple times my query return incorrect values as the number from which the formula subtracts is never changed.

See attached database.

 

[smile]

Done some more tweaking now, but how to integrate "query2" column "expr1" that lists remaining stock items for that item to the "sell" query?

If I just drag it in the design view I get multipe ID's see "sell query integrated"

see attached db example.