I want to make a simple view that allows the to see if the sum of stock from different warehouses are >0 and < that the minimum stock of said product.

Here is the code:

```
SELECT a.code, a.description, a.stk_min , b.Stk_Qty
FROM a 
INNER JOIN b ON a.code = b.productcode
WHERE a.stk_min > 0 and 

     (SELECT SUM(b.Stk_Qty )
     FROM b
     INNER JOIN a ON a.code = b.productcode
     Group By a.code) <= a.stk_min

```

And of course I get the error

> 
> Subquery returned more than 1 value. This is not permitted when the subquery follows `=`, `!=`, `<`, `<=`, `>`, `>=` or when the subquery is used as an expression.
> 
> 
> 

Is there something I can do to change this?