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码字定式之SQL(4)

时间:2014-11-27 12:43:05      阅读:268      评论:0      收藏:0      [点我收藏+]

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一些子查询
  1. select empno, ename from emp where mgr in
  2. (select empno from emp where job=‘MANAGER‘);
  3. select * from dept where deptno not in (select distinct deptno from emp);
  4. select * from dept where deptno not in (select deptno from emp);
  5. select empno, ename, sal from emp where mgr=
  6. (select empno from emp where ename=‘SCOTT‘);
  7. select * from emp where sal > 1.4*
  8. (select avg(sal) from emp);
  1. insert into dept(deptno, dname, loc) select 50, ‘TRAINING‘, ‘PEKING‘ from dual;
  2. update emp set sal=sal*1.2 where exists (select 1 from dept where deptno=emp.deptno and loc=‘DALLAS‘);
在写一条孔乙己式样的sql:
update emp set sal=sal*1.2 where exists (select avg(sal) from dept);

简单的层次查询
–-查询7788号雇员的下属和下属的下属……
select level, t.* from emp t start with empno=7788 connect by prior empno=mgr;
–-查询7788号雇员的的上司和上司的上司……
select level, t.* from emp t start with empno=7788 connect by empno=prior mgr;   




码字定式之SQL(4)

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原文地址:http://www.cnblogs.com/mahun/p/4125951.html

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