select

    e.ename,t.*

    from

    (select max(sal) as sal,deptno from emp group by deptno) t

    join

    emp e

    on

    e.deptno=t.deptno and e.sal=t.sal;

 select

    e.ename,e.sal

    from

    (select deptno,avg(sal) as sal from emp group by deptno) t

    join

    emp e

    on

e.deptno=t.deptno and e.sal>t.sal;

select

e.deptno,avg(s.grade)

from emp e

join

salgrade s

on

e.sal between s.losal and s.hisal

group by e.deptno;

select ename from emp order by sal desc limit 1;

自连接

select t.deptno from

   (select deptno,avg(sal) as avgsal from emp group by deptno) t

   where

   t.avgsal=(select max(t.avgsal)from (select deptno,avg(sal) as avgsal from emp group by deptno) t);

select deptno from emp group by deptno order by avg(sal) desc limit 1

select d.dname

from

(select t.deptno from

(select deptno,avg(sal) as avgsal from emp group by deptno) t

where

t.avgsal=(select max(t.avgsal)from (select deptno,avg(sal) as avgsal from emp group by deptno) t)) m

Join

dept d

on

m.deptno =d.deptno;

select d.dname

from

(select deptno from emp group by deptno order by avg(sal) desc limit 1) t

join

dept d

on

d.deptno=t.deptno;

select d.dname

from

(select t.*,s.grade from(select deptno ,avg(sal) as avgsal from emp group by deptno) t

 join

salgrade s

on

t.avgsal between s.losal and s.hisal order by s.grade limit 1) t

join

dept d

on

d.deptno=t.deptno;

(有问题)

select max(sal)from emp where empno not in(select distinct mgr from emp where mgr is not null)

select ename from emp where empno in(select distinct mgr from emp where mgr is not null);

select t.ename,t.sal

from

(select ename,sal from emp where empnoi n(select distinct mgr from emp where mgr is not null)) t

where

t.sal>(select max(sal)from emp where empno not in(select distinct mgr from emp where mgr is not null));

select ename,sal from emp order by sal desc limit 0,5;

select ename,sal from emp order by sal desc limit 5,5;

select ename,hiredate from emp order by hiredate desc limit 0,5;

select t.grade,count(*)

from

(select s.grade from

emp e

join

salgrade s

on

e.sal between s.losal and s.hisal) t

group by t.grade;

(

  SNO      VARCHAR(200),

  CNO      VARCHAR(200),

  SCGRADE  VARCHAR(200)

);

(

  SNO    VARCHAR(200 ),

  SNAME  VARCHAR(200)

);

(

  CNO       VARCHAR(200),

  CNAME     VARCHAR(200),

  CTEACHER  VARCHAR(200)

);

INSERT INTO C ( CNO, CNAME, CTEACHER ) VALUES ( '1', '语文', '张');

INSERT INTO C ( CNO, CNAME, CTEACHER ) VALUES ( '2', '政治', '王');

INSERT INTO C ( CNO, CNAME, CTEACHER ) VALUES ( '3', '英语', '李');

INSERT INTO C ( CNO, CNAME, CTEACHER ) VALUES ( '4', '数学', '赵');

INSERT INTO C ( CNO, CNAME, CTEACHER ) VALUES ( '5', '物理', '黎明');

commit;

INSERT INTO S ( SNO, SNAME ) VALUES ( '1', '学生1');

INSERT INTO S ( SNO, SNAME ) VALUES ( '2', '学生2');

INSERT INTO S ( SNO, SNAME ) VALUES ( '3', '学生3');

INSERT INTO S ( SNO, SNAME ) VALUES ( '4', '学生4');

commit;

commit;

select a.ename,b.ename

from

emp a

left join

emp b

on

a.mgr=b.empno;

select t.empno,t.ename,d.dname

from

(select a.empno,a.ename,a.deptno

from

emp a

join

emp b

on

a.hiredate<b.hiredate and a.mgr=b.empno) t

join

dept d

on

d.deptno=t.deptno;

select d.dname,e.*

from

dept d

left join

emp e

on

d.deptno=e.deptno;

select

d.dname,t.count

from

(select deptno,count(deptno) as count from emp group by deptno having count>=5) t

join

dept d

on

d.deptno=t.deptno;

select *from emp where sal>(select sal from emp where ename='SMITH');

select e.ename,d.dname,t.cc

from

(select ename,deptno from emp where job='CLERK') e

join

dept d

on

d.deptno=e.deptno

join

( select deptno,count(deptno) as cc from emp group by deptno) t

on

t.deptno=e.deptno;

select job,count(ename) from emp where sal>1500 group by job;

select t.ename from (select e.ename,d.dname from emp e join dept d on e.deptno=d.deptno) t where t.dname='SALES';

select t.ename,d.dname,e.ename,s.grade

from

(select ename,deptno,sal,mgr from emp where sal>(select avg(sal) from emp)) t

join

dept d

on

d.deptno=t.deptno

join

salgrade s

on

t.sal between s.losal and s.hisal

left join

emp e

on

t.mgr=e.empno;

select t.ename,d.dname

from

(select ename,deptno from emp where job=(select job from emp where ename='SCOTT')and ename<>'SCOTT') t

join

dept d

on

t.deptno=d.deptno;

select ename,sal from emp where sal in(select distinct sal from emp where deptno=30) and deptno<>30;

 select

d.*,count(e.ename),ifnull(avg(sal),0),ifnull(avg(timestampdiff(YEAR,hiredate,now())),0)as avgyear

from

emp e

right join

dept d

on

 d.deptno=e.deptno

group by

d.deptno,d.dname,d.loc;

select t.ename,d.dname,t.sal

from

(select ename,deptno,sal from emp) t

join

dept d

on

d.deptno=t.deptno;

select

d.deptno,d.dname,d.loc,t.count as '人数'

from

(select deptno,count(deptno) as count from emp group by deptno) t

right join

dept d

on

d. deptno=t.deptno;

select

e.*

from

(select job,min(sal) as minsal from emp group by job) t

join

emp e

on

e.job=t.job and e.sal=t.minsal;

select min(sal),deptno from emp where job='MANAGER' group by deptno;

select ename,sal*12 as income from emp order by income asc;

select t.ename,e.ename

from

( select empno,ename,sal from emp where sal>3000 and empno in(select distinct mgr from emp where mgr is not null)) t

join

emp e

on

e.mgr=t.empno;

select d.dname,t.countdeptno,t.sumsal

from

(select deptno,count(deptno) as countdeptno,sum(sal) as sumsal from emp group by deptno) t

join

(select deptno from emp where ename like'%S%' group by deptno) m

on

m.deptno=t.deptno

join

dept d

on

d.deptno=t.deptno;

update emp_bak

set sal=sal*1.1

where

timestampdiff(YEAR,hiredate,now())>30;