2018-12-28

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1.答select a.deptno,a.dname,a.loc,count(*) from dept a join emp b on a.deptno = b.deptno group by a.deptno;

2.答select * from emp where sal > (select sal from emp where ename = 'e');

3.答select a.ename 员工姓名,b.ename 直接上级姓名 from emp a left join emp b on a.mgr = b.empno

4.答update emp set mgr='1009' where job='文员';

5.答select b.empno,b.ename,b.job,a.dname,(select ename from emp where empno = ifnull(b.mgr,'1009')) 上级姓名,(select grade from salgrade where b.sal between lowsal and hisal) 薪资等级 from dept a join emp b on a.deptno = b.deptno where b.sal > (select avg(sal) from emp);