oracle查询笔记(2)

11.在多行子查询中使用all操作符

all表示所有，用在子句中

select ename,sal from emp where sal>all(select sal from emp where deptno=30);

等同于

select ename,sal from emp where sal>(select max(sal) from emp where deptno=30);

12.多行子查询中使用any操作符

select ename,sal from emp where sal>any(select sal from emp where deptno=30);

等同于

select ename,sal from emp where sal>(select min(sal) from emp where deptno=30);

13.多列子查询

select * from emp where (deptno,job)=(select deptno,job from emp where ename='SMITH');

14.oracle分页

1)rownum分页

  select * from

  (select rownum rn,a1.* from emp a1 where rownum<9)

  where rn>4;

  注意：所有的改动都只改里面的查询

2)rowid分页(效率是rownum的3倍)

  select * from emp where rowid in

  (select rid from

  (select rownum rn,rid from

  (select rowid rid,empno from emp order by empno desc)

  where rownum<10)

  where rn>3)

  order by empno desc;

15.如何显示高于自己部门平均工资的员工的信息

select a1.* from emp a1,(select deptno,avg(sal) avgsal from emp group by deptno) a2 where a1.deptno=a2.deptno and a1.sal>a2.avgsal;

16.用查询结果创建新表

create table emp2 (empno,ename,sal) as

select empno,ename,sal from emp;