desc emp;
Name Null? Type
----------------------------------------- -------- ----------------------------
EMPNO NOT NULL NUMBER(4)
ENAME VARCHAR2(10)
JOB VARCHAR2(9)
MGR NUMBER(4)
HIREDATE DATE
SAL NUMBER(7,2)
COMM NUMBER(7,2)
DEPTNO NUMBER(2)
既要显示部门的平均工资，也要显示岗位的平均工资。那么可以使用GROUPING SET函数。
SQL> select deptno,job,avg(sal) from emp group by grouping sets(deptno,job);
DEPTNO JOB AVG(SAL)
---------- --------- ----------
CLERK 1037.5
SALESMAN 1400
PRESIDENT 5000
MANAGER 2758.33333
ANALYST 3000
30 1566.66667
20 2175
10 2916.66667
8 rows selected.
