MySQL find duplicates based on another column value

Question

I have the following table

+----+------+-------+
| id | user | value |
+----+------+-------+
|  1 |  10  |   A   |
|  2 |  12  |   B   |
|  3 |  24  |   A   |
|  4 |  33  |   C   |
+----+------+-------+

I want to retreive all the duplicates users that have the same key

+----+------+-------+
| id | user | value |
+----+------+-------+
|  1 |  10  |   A   |
|  3 |  24  |   A   |
+----+------+-------+

I've tried that with no luck

SELECT DISTINCT A.user, A.value
FROM table as A
INNER JOIN ( SELECT value FROM table GROUP BY value HAVING COUNT(value) > 1 ) AS B
ON A.value = B.value 

Answer 1

You may try below query -

SELECT id, user, value
FROM YUOR_TABLE T1
WHERE EXISTS (SELECT 1
              FROM YOUR_TABLE T2
              WHERE T1.value = T2.value
              AND T1.user <> T2.user)