Question

Not sure how to explain this, as I have only basic SQL knowledge. I need help with some logic to signal a user when a unique string is referenced more than once in a composite primary key.

A table I use contains a composite primary key which ties a unique “ItemCode” to a repeating “WarehouseCode”. The “QuantityOnHand” column lists how much we have of an item in each warehouse:

     _____PK_______
    |              |
ItemCode  |  WarehouseCode  |  QuantityOnHand
---------------------------------------------
   001             A                 100
   001             B                 500
   002             A                 600
   003             B                 250

etc.

How do I “signal” (create a boolean value?) when ItemCode 001 is in two separate warehouses?

The end result is a crystal report which somehow alerts the user when an item’s total quantity is split between two warehouses.

Thanks

Answer 1

Utilise GROUP BY and HAVING. For example this query will return a list of ItemCodes and a count of how many warehouses they are in where that count is greater than 1.

SELECT ItemCode, COUNT(*)
FROM table
GROUP BY ItemCode
HAVING COUNT(*) > 1