select嵌套查询

--单行子查询

select ename,sal,deptno from emp where deptno=(select deptno from emp where ename='SCOTT')

select ename,sal,deptno from emp where deptno=(select deptno from emp where ename = 'SCOTT')

--多行子查询

select ename,sal,deptno,job from emp where job in (select distinct job from emp where deptno = 10)

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

select ename,sal from emp where deptno = 30

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

--多列子查询

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

update emp
set sal=1500,comm=30 where ename = 'CLARK'

select ename,sal,comm from emp where ename = 'CLARK'

select ename,sal,comm,deptno from emp where(sal,nvl(comm,-1)) in (select sal,nvl(comm,-1) from emp where deptno =30)

select ename,sal,comm from emp where deptno=30

select ename,sal,comm,deptno from emp where sal in (select sal from emp where deptno = 30)and nvl(comm,-1)in(select nvl(comm,-1)from emp where deptno = 30)