How to get rows having sum equal to given value

Question

There is table contain

ID     Qty
----------
1       2
2       4
3       1
4       5

Now if i had to choose rows where sum of Qty equals to

Answer 1

If you want it to be exactly always three numbers that add to 10, then this

SELECT
  *
FROM 
  MyTable t1
  JOIN
  MyTable t2 ON t1.ID <> t2.ID 
  JOIN
  MyTable t3 ON t1.ID <> t3.ID AND t2.ID <> t3.ID
WHERE
  t1.Qty + t2.Qty + t3.Qty = 10

If you want 2 or 4 or 5 numbers then you can't really do it in SQL

Edit:

• Updated to ignore by ID not Qty
• And again: If you want 2 or 4 or 5 numbers then you can't really do it in SQL