GROUPING
Syntax
grouping::=
Text description of grouping
Purpose
GROUPING distinguishes superaggregate rows from regular grouped rows. GROUP BY extensions such as ROLLUP and CUBE produce superaggregate rows where the set of all values is represented by null. Using the GROUPING function, you can distinguish a null representing the set of all values in a superaggregate row from a null in a regular row.
The expr in the GROUPING function must match one of the expressions in the GROUP BY clause. The function returns a value of 1 if the value of expr in the row is a null representing the set of all values. Otherwise, it returns zero. The datatype of the value returned by the GROUPING function is Oracle NUMBER.
| See Also: group_by_clause of the |
Examples
In the following example, which uses the sample tables hr.departments and hr.employees, if the GROUPING function returns 1 (indicating a superaggregate row rather than a regular row from the table), then the string "All Jobs" appears in the "JOB" column instead of the null that would otherwise appear:
SELECT DECODE(GROUPING(department_name), 1, 'All Departments', department_name) AS department, DECODE(GROUPING(job_id), 1, 'All Jobs', job_id) AS job, COUNT(*) "Total Empl", AVG(salary) * 12 "Average Sal" FROM employees e, departments d WHERE d.department_id = e.department_id GROUP BY ROLLUP (department_name, job_id); DEPARTMENT JOB Total Empl Average Sal ------------------------------ ---------- ---------- ----------- Accounting AC_ACCOUNT 1 99600 Accounting AC_MGR 1 144000 Accounting All Jobs 2 121800 Administration AD_ASST 1 52800 Administration All Jobs 1 52800 Executive AD_PRES 1 288000 Executive AD_VP 2 204000 Executive All Jobs 3 232000 Finance FI_ACCOUNT 5 95040 Finance FI_MGR 1 144000 Finance All Jobs 6 103200 . . .
