SQL duplicates with different primary keys

Question

I have a table in this form:

id | firstname | lastname
---+-----------+----------
1  | alex      | marti
2  | mark      | finger
3  | alex      | marti
4  | ted          


        

Answer 1

you can do the following to show all the id column values

SELECT GROUP_CONCAT(DISTINCT id SEPARATOR ',') AS ids, firstname, lastname FROM t GROUP BY firstname, lastname HAVING COUNT(*) > 1

This should show something like this:

ids | firstname | lastname
----+-----------+----------
1,3 | alex      | marti