ORACLE ROLLUP CUBE

 Oracle的GROUP BY语句除了最基本的语法外，还支持ROLLUP和CUBE语句。如果是ROLLUP(A, B, C)的话，首先会对(A、B、C)进行GROUP BY，然后对(A、B)进行GROUP BY，然后是(A)进行GROUP BY，最后对全表进行GROUP BY操作。如果是GROUP BY CUBE(A, B, C)，则首先会对(A、B、C)进行GROUP BY，然后依次是(A、B)，(A、C)，(A)，(B、C)，(B)，(C)，最后对全表进行GROUP BY操作。

如下SQL

select t.*, t.rowid from group_test t;

MANAGER 20 2975 AAAQMEAAEAAEGk/AAA
SALESMAN 30 1250 AAAQMEAAEAAEGk/AAB
MANAGER 30 2850 AAAQMEAAEAAEGk/AAC
MANAGER 10 2450 AAAQMEAAEAAEGk/AAD
ANALYST 20 3000 AAAQMEAAEAAEGk/AAE
PRESIDENT 10 5000 AAAQMEAAEAAEGk/AAF
SALESMAN 30 1500 AAAQMEAAEAAEGk/AAG
CLERK 20 1100 AAAQMEAAEAAEGk/AAH
CLERK 30 950 AAAQMEAAEAAEGk/AAI
ANALYST 20 3000 AAAQMEAAEAAEGk/AAJ
CLERK 10 1300 AAAQMEAAEAAEGk/AAK
CLERK 20 800 AAAQMEAAEAAEGlAAAA
SALESMAN 30 1600 AAAQMEAAEAAEGlAAAB
SALESMAN 30 1250 AAAQMEAAEAAEGlAAAC

select job, deptno, sum(sal) total_sal
  from group_test
 group by rollup(job, deptno);

JOB       DEPTNO      TOTAL_SAL
CLERK    10             1300
CLERK    20             1900
CLERK    30             950
CLERK                    4150
ANALYST 20           6000
ANALYST                6000
MANAGER 10          2450
MANAGER 20          2975
MANAGER 30          2850
MANAGER               8275
SALESMAN 30         5600
SALESMAN              5600
PRESIDENT 10         5000
PRESIDENT              5000
                             29025

 select job, deptno, sum(sal) total_sal
  from group_test
 group by cube(job, deptno);

JOB	DEPTNO	TOTAL_SAL
		29025
	10	8750
	20	10875
	30	9400
CLERK		4150
CLERK	10	1300
CLERK	20	1900
CLERK	30	950
ANALYST		6000
ANALYST	20	6000
MANAGER		8275
MANAGER	10	2450
MANAGER	20	2975
MANAGER	30	2850
SALESMAN		5600
SALESMAN	30	5600
PRESIDENT		5000
PRESIDENT	10	5000

select decode(grouping_id(job, deptno), 1, '合计', job || deptno) as group_col,
       sum(sal) total_sal
  from group_test
 group by rollup(job, deptno);

GROUP_COL	TOTAL_SAL
CLERK10	1300
CLERK20	1900
CLERK30	950
合计	4150
ANALYST20	6000
合计	6000
MANAGER10	2450
MANAGER20	2975
MANAGER30	2850
合计	8275
SALESMAN30	5600
合计	5600
PRESIDENT10	5000
合计	5000
	29025