Question

I have two tables (Items and Item_Types), and I want to do something like the following as a formula in a calculated column in the Item_Types table:

SELECT SUM(Items.Qty_In_Stock) FROM Items WHERE Items.Item_Type = Item_Types.ID

But Management Studio isn’t liking it.

How can I do this? Or have I just got my syntax wrong? I’m not great with SQL.

Thanks

EDIT: I think I need to be more specific.

One ItemType can have many Items.

Each Item has a Qty_In_Stock field.

I want to get a sum of all Qty_In_Stock fields where Items.Item_Type = Item_Types.ID – not just a sum of the entire column.

Cheers

Answer 1

Assuming you are trying to show the available qty for each item type:
I would recommend creating a view that shows this information:
You will need to “GROUP BY” the item type.

CREATE VIEW Item_Types_Qty_In_Stock
AS

SELECT it.ID, SUM(i.Qty_In_Stock) AS QtyInStock FROM Items i
INNER JOIN Item_Types it ON i.Item_Type = it.ID 
GROUP BY it.ID
GO

Once you have created the view, you can query it as if it were a table:

SELECT * FROM Item_Types_Qty_In_Stock