Question

I’m not great with sql and I’ve tried this a lot of different ways and can’t come up with a reliable solution.
Basically I have

I need a query that will tell how many unique instances of nid show up for a combination of tid. Basically count with two or more conditionals and only return the number of rows that met all of the conditions. The combination of tid s can be more than 2 or more numbers…this will obviously require adding to the query and this is fine (I dont expect a query that accepts an array if that makes sense)…I just need the logic of the query sound.

I need to be able to pass the tid ‘s of 35 & 45 and receive back “2” meaning two complete matches. The tid 35 & 45 both appear with nid 4 & 10, but since tid 45 doesn’t appear in nid 2, it should not count it. I hope that makes sense.

When testing against:

26,27 it should reply “2”

35,27 should reply “2”

31,35 should reply “1”

26,27,45 should reply “1”

Answer 1

Showing the nid: 4 and 10

SELECT nid
FROM taxonomy_index
WHERE tid IN (35,45)               --- list of tid to check
GROUP BY nid
HAVING COUNT(DISTINCT tid) = 2     --- count of numbers in list

Counting them:

SELECT COUNT(*)
FROM
  ( SELECT nid
    FROM taxonomy_index
    WHERE tid IN (35,45)
    GROUP BY nid
    HAVING COUNT(DISTINCT tid) = 2
  ) AS grp

If the combination (nid,tid) is unique, then the COUNT(DISTINCT tid) can be replaced with COUNT(*).

Another way is:

SELECT COUNT(DISTINCT nid)
FROM taxonomy_index a
WHERE NOT EXISTS
      ( SELECT *
        FROM taxonomy_index b
        WHERE b.tid IN (35,45)
          AND NOT EXISTS
              ( SELECT *
                FROM taxonomy_index c
                WHERE c.tid = b.tid
                  AND c.nid = a.nid
              )
      )