oracle---plsql---示例laobai

select * from scott.emp;
--1 列出emp表中各部门的部门号，最高工资，最低工资
    select deptno,max(sal),min(sal) from scott.emp group by deptno;

2 列出emp表中各部门job为'CLERK'的员工的最低工资，最高工资
 select min(sal),max(sal) from scott.emp where job='CLERK'

3 --对于emp中最低工资小于13000的部门，
--列出job为'CLERK'的员工的 (部门号)，最低工资，最高工资
  select min(sal),max(sal) from scott.emp where job='CLERK' and deptno in
  (
    select deptno from scott.emp group by deptno having min(sal)<'13000'
  )  

4 根据部门号由高而低，工资有低而高列出每个员工的姓名，部门号，工资

select ename,deptno,sal from scott.emp order by deptno desc,sal

5列出'张三'所在部门中每个员工的姓名与部门号
  select ename,deptno from
  scott.emp where deptno in
    (
     select deptno from scott.emp where ename='WARD'
     )

6列出每个员工的姓名，工作，部门号，部门名
 select ename,job,scott.emp.deptno ,scott.dept.dname
  from scott.emp  inner join scott.dept on scott.emp.deptno = scott.dept.deptno;

 select ename,job,scott.emp.deptno ,scott.dept.dname
  from scott.emp , scott.dept where
   scott.emp.deptno = scott.dept.deptno;

7列出emp中工作为'CLERK'的员工的姓名，工作，部门号，部门名
 select ename,job,scott.emp.deptno ,scott.dept.dname
  from scott.emp , scott.dept
  where
   scott.emp.deptno = scott.dept.deptno and job='CLERK';

8 对于emp中有管理者的员工，列出姓名，管理者姓名（管理者外键为mgr）
 同表自关联。适合于设计多级菜单，多级种类。
select s1.ename,s2.ename as 管理者
from
 (select * from scott.emp where mgr is not null) s1,scott.emp s2
 where s1.mgr = s2.empno;

9对于dept表中，列出所有部门名，部门号，
select * from
同时列出各部门工作为'CLERK'的员工名与工作
select d.*,e.ename,e.job from scott.dept d  join
 (select deptno,ename,job from scott.emp where job='CLERK') e
 on d.deptno = e.deptno;

10 对于工资高于本部门平均水平的员工，列出部门号，姓名，工资，按部门号排序
  select deptno,ename,sal from scott.emp e
  where sal>(select avg(sal) from scott.emp where deptno = e.deptno)
  order by deptno;

  select deptno,avg(sal) from scott.emp group by deptno

11 对于emp，列出各个部门中工资高于本部门平均水平的员工数和部门号，
按部门号排序
  select  count(1) 员工数,deptno from
  ( select deptno,ename,sal from scott.emp e
  where sal>(select avg(sal) from scott.emp where deptno = e.deptno)
  ) group by deptno order by deptno;

12   对于emp中工资高于本部门平均水平，人数多与1人的，列出部门号，人数，按部门号排序
 select  count(1) 员工数,deptno from
  ( select deptno,ename,sal from scott.emp e
  where sal>(select avg(sal) from scott.emp where deptno = e.deptno)
  ) group by deptno having count(1)>1 order by deptno;

13 对于emp中低于自己工资至少5人的员工，列出其部门号，姓名，工资，
[以及工资少于自己的人数]
 --找出有比自己工资少的人
select t.*  from
(
select deptno,ename,sal,empno from scott.emp
  where sal not in
  (
    select  sal from (
   select distinct(sal) ,rownum r from scott.emp  order by  sal )
    where r<6
    )
 ) t ,scott.emp where scott.emp.sal<t.sal;

    select a.deptno,a.ename,a.sal,(select count(b.ename) from
    emp as b where b.sal<a.sal) as 人数 from scott.emp as a
    where (select count(b.ename) from emp as b where b.sal<a.sal)>5