实际应用中我们可以通过sum()统计出组中的总计或者是累加值,具体示例如下:
1.创建演示表
create table emp as select * from scott.emp; alter table emp add constraint emp_pk primary key (empno); create table dept as select * from scott.dept; alter table dept add constraint dept_pk primary key (deptno);
2. sum()语句如下:
select deptno, ename, sal, -- 按照部门薪水累加(order by改变了分析函数的作用,只工作在当前行和前一行,而不是所有行) sum (sal) over (partition by deptno order by sal) CumDeptTot, sum (sal) over (partition by deptno) SalByDept, -- 统计一个部门的薪水 sum (sal) over ( order by deptno,sal) CumTot, -- 所有雇员的薪水一行一行的累加 sum (sal) over () TotSal -- 统计总薪水 from emp order by deptno, sal
3. 结果如下:
10 MILLER 1300.00 1300 8750 1300 29025 10 CLARK 2450.00 3750 8750 3750 29025 10 KING 5000.00 8750 8750 8750 29025 20 SMITH 800.00 800 10875 9550 29025 20 ADAMS 1100.00 1900 10875 10650 29025 20 JONES 2975.00 4875 10875 13625 29025 20 SCOTT 3000.00 10875 10875 19625 29025 20 FORD 3000.00 10875 10875 19625 29025 30 JAMES 950.00 950 9400 20575 29025 30 WARD 1250.00 3450 9400 23075 29025 30 MARTIN 1250.00 3450 9400 23075 29025 30 TURNER 1500.00 4950 9400 24575 29025 30 ALLEN 1600.00 6550 9400 26175 29025 30 BLAKE 2850.00 9400 9400 29025 29025