Oracle数据库中的rollup配合group by命令使用，可以提供信息汇总功能（与"小计"相似）

示例如下：

SQL> select job,deptno,sal from emp;

JOB DEPTNO SAL

--------- --------- ---------

CLERK 20 800

SALESMAN 30 1600

SALESMAN 30 1250

MANAGER 20 2975

SALESMAN 30 1250

MANAGER 30 2850

MANAGER 10 2450

ANALYST 20 3000

PRESIDENT 10 5000

SALESMAN 30 1500

CLERK 20 1100

CLERK 30 950

ANALYST 20 3000

CLERK 10 1300

已选择14行。

SQL> select job,deptno,sum(sal) total_sal

from emp group by rollup(job,deptno);

JOB DEPTNO TOTAL_SAL

--------- --------- ---------

ANALYST 20 6000

ANALYST 6000

CLERK 10 1300

CLERK 20 1900

CLERK 30 950

CLERK 4150

MANAGER 10 2450

MANAGER 20 2975

MANAGER 30 2850

MANAGER 8275

PRESIDENT 10 5000

PRESIDENT 5000

SALESMAN 30 5600

SALESMAN 5600

29025

已选择15行。

SQL>