Question

I have a table A with column B_ID refering to B_ID in table B
Table B has B_ID as primary key and C_ID refering to C_ID in table C

I want to select from A join B on A_ID where B.C_ID = 5 AND B.C_ID = 4

for example when I do this:

select from A join B on B.A_ID = A.A_ID

If the result is :

A_ID  |  B_ID  |  C_ID
 1    |   1    |   4
 1    |   2    |   5

Then I want the query to return both rows
But if the result is :

A_ID  |  B_ID  |  C_ID
 1    |   1    |   4

I want the query to return 0 rows.

Answer 1

Try this

SELECT
    whatever
FROM
    A
    INNER JOIN B
        ON A.A_ID = B.A_ID
WHERE
    B.C_ID IN (4, 5)

or

SELECT
    whatever
FROM
    A
    INNER JOIN B
        ON A.A_ID = B.A_ID
WHERE
    B.C_ID = 4 OR B.C_ID = 5

---

UPDATE

If you want only matching pairs

SELECT
    whatever
FROM
    A
    INNER JOIN B
        ON A.A_ID = B.A_ID
WHERE
    A.A_ID IN (SELECT A_ID
               FROM B
               WHERE C_ID IN (4, 5)
               GROUP BY A_ID
               HAVING COUNT(*) = 2) AND
    B.C_ID IN (4, 5)

The sub-select groups by A_ID and counts the records. The HAVING clause works like the WHERE clause but is executed after grouping. So the inner select returns only A_IDs corresponding to (4, 5)-pairs of C_ID. The whole query always returns an even number of records like

A_ID  |  B_ID  |  C_ID
 1    |   1    |   4
 1    |   2    |   5
 2    |   3    |   4
 2    |   4    |   5

---

EDIT

If you only want A_IDs where not only C_IDs 4 and 5 are present but where no further C_IDs exist then change the query to

SELECT B.*
FROM A INNER JOIN B ON A.A_ID = B.A_ID
WHERE B.C_ID IN (4, 5) AND
      A.A_ID IN (SELECT A_ID
                 FROM B
                 GROUP BY A_ID
                 HAVING MIN(C_ID)=4 AND MAX(C_ID)=5 AND COUNT(*)=2)

If the two numbers (4 and 5 in this example) are always contiguous, you can drop the COUNT(*)=2 part.

(Note: accoring to one of your comments the join is on the A_ID column. I changed that in all my examples.)

UPDATE by Robin

Thanks, with your help I came up with this:

SELECT
    *
FROM
    A a
    INNER JOIN B
        ON a.A_ID = B.A_ID
WHERE
    (SELECT COUNT(*) FROM B b WHERE b.A_ID = a.A_ID and C_ID IN (4, 5)) =
 (SELECT COUNT(*) FROM A aa INNER JOIN B b ON aa.A_ID = b.A_ID WHERE b.A_ID = a.A_ID)