Group_id – Oracle SQL Function

GROUP_ID assigns a number to each group defined in a GROUP BY clause,

GROUP_ID can be used to easily see duplicated groups in query results.

Example:

select avg(salary), mgr_id, group_id() gid from EMP group by mgr_id;

AVG(SALARY) MGR_ID GID
———————- ———— —–
11000 100 0
12300 101 0
45643 102 0

This example shows no duplicate groups.