Question

Ive been trying to query where a group of row values repeat exactly . like this:

id       part_id    supplier    quantity
 1          1         A            20
 2          1         B            30

 3          2         A            11
 4          2         B            30

 5          3         A            20
 6          3         B            30  

we can assume that each part_id will always have both A and B as the suppliers.

My problem is that I want to query for part_id where A=20 and B=30.

The result would be part_id : 1 and 3

How do I do that given that A and B are in 2 different rows? Is this possible?

Answer 1

A sub-select would do:

SELECT id, part_id, supplier, quantity
FROM yourtable
WHERE part_id IN (
   SELECT DISTINCT part_id
   FROM yourtable
   WHERE ((supplier = 'A') and (quantity = 20)) 
      OR ((supplier = 'B') and (quantity = 30))
)

---

edit, ok. given the new info, try this for the subselect:

 SELECT part_id
 FROM yourtable
 WHERE ((supplier = 'A') and (quantity = 20)) 
      OR ((supplier = 'B') and (quantity = 30))
 GROUP BY part_id
 HAVING COUNT(part_id) = 2

find all the records where the a/b stuff maches, group by the part_id, but only return the part_ids where BOTH a/b parts match. so the case where a=11 will get ignored, because the count would only be 1 in that particular case.