1SELECT username, email, COUNT(*)
2FROM users
3GROUP BY username, email
4HAVING COUNT(*) > 1
5
1SELECT name, COUNT(email)
2FROM users
3GROUP BY email
4HAVING COUNT(email) > 1
1Multiple field=
2SELECT username, email, COUNT(*)
3FROM users
4GROUP BY username, email
5HAVING COUNT(*) > 1
6
7Single field=
8SELECT _column, COUNT(*)
9FROM _table
10GROUP BY _column
11HAVING COUNT(*) > 1