Question

I’m trying to make a query, but I can’t find a way to do it.

So I got 3 tables

Table Card (card_id)

Table Level(leve_id, leve_desc)

Table CardDetails(cade_id, card_id, leve_id)

So here is the problem : Each cards got a list of details.

I want a query to count for each cards, the number of cards who have the exact same details, excluding the card it-self. Which means the same list of leve_id.

Is it possible to achieve it in plain t-sql?

I hope I have been clear enough, if not, I’ll try to explain better what I need.

Edit:

I don’t really need to know which cards it is for the moment, but it would sure credit bonus points if it did.

Edit #2:
So lets say
table Card (card_id)
1,2,3,4,5,6

Table level (leve_id, leve_desc)
(1, Level 1), (2,Level 2), (3,Level 3), (4,Level 4), (5, Level5), (6, Level6)

Table CardDetails (card_id, leve_id)
(1, 1), (1, 3), (1, 4), (2, 1), (2, 2), (3, 1)
(3, 3), (3, 4), (4, 5), (5, 1), (5, 2), (5, 3)
(5, 4), (5, 5), (5, 6), (6, 1), (6, 3), (6, 4)

So, the result should be :

Card_id   Nbr_Cards
1    ..   2
2    ..   0
3    ..   2
4    ..   0
5    ..   0
6    ..   2

Answer 1

If I understand you correctly you want something like this

SELECT * 
FROM   cards c 
       INNER JOIN carddetails cd 
         ON c.card_id = cd.card_id 
       INNER JOIN (SELECT cade_id, 
                          leve_id 
                   FROM   carddetails 
                   GROUP  BY cade_id, 
                             leve_id 
                   HAVING COUNT (card_id) > 1)dups 
         ON cd.cade_id = dups.cade_id 
            AND cd.leve_id = dups.leve_id 

Or if you like COUNT OVER

with dups as  (
SELECT 
   COUNT(CARD_ID)  OVER (PARTITION BY cade_id, leve_id) cardCount
   cade_id,
   leve_id
FROM  carddetails 
)
    SELECT * 
    FROM   cards c 
           INNER JOIN carddetails cd 
             ON c.card_id = cd.card_id 
           INNER JOIN  dups 
             ON cd.cade_id = dups.cade_id 
                AND cd.leve_id = dups.leve_id 
    WHERE cardCount > 1