create table dept
(
deptno varchar(10) primary key,
dname varchar(10)
);
create table emp
(
empno varchar(10) primary key,
ename varchar(10),
job varchar(10),
mgr varchar(10),
sal varchar(10),
deptno varchar(10) references dept(deptno)
);
drop table dept;
drop table emp;
insert into dept values ('1','事業(yè)部');
insert into dept values ('2','銷售部');
insert into dept values ('3','技術(shù)部');
insert into emp values ('01','jacky','clerk','tom','1000','1');
insert into emp values ('02','tom','clerk','','2000','1');
insert into emp values ('07','biddy','clerk','','2000','1');
insert into emp values ('03','jenny','sales','pretty','600','2');
insert into emp values ('04','pretty','sales','','800','2');
insert into emp values ('05','buddy','jishu','canndy','1000','3');
insert into emp values ('06','canndy','jishu','','1500','3');
select * from dept;
select * from emp;
1.列出emp表中各部門的部門號(hào)，最高工資，最低工資
select e.deptno ,max(sal) ,min(sal) from emp as e group by e.deptno;
解析：各部門 提示：分組查詢，所以用group by
2 列出emp表中各部門job為'CLERK'的員工的最低工資，最高工資
select e.deptno ,max(sal) ,min(sal) from emp as e where e.job="CLERK" group by e.deptno;
解析：各部門 提示：分組查詢， job提示：條件查詢，所以用到 group by 和 where
3 對(duì)于emp中最低工資小于2000的部門，列出job為'CLERK'的員工的部門號(hào)，最低工資，最高工資
select b.deptno ,max(sal) ,min(sal) from emp as b where b.job="CLERK"
and (select min(sal) from emp as a where a.deptno=b.deptno)<2000 group by b.deptno;
解析：以上面兩個(gè)題為基礎(chǔ)，“emp中最低工資小于2000的部門”只是一個(gè)條件而已。
4 據(jù)部門號(hào)由高而低，工資有低而高列出每個(gè)員工的姓名，部門號(hào)，工資
select * from emp as b order by b.deptno desc ,b.sal asc;
解析：“部門號(hào)由高而低，工資有低”提示：需要排序，所以用到 order by 和 desc asc
5 列出'buddy'所在部門中每個(gè)員工的姓名與部門號(hào)
select * from emp as b where b.deptno=(select a.deptno from emp as a where a.ename="buddy");
解析：“'buddy'所在部門”提示找出他所在的部門號(hào)，所以可以理解“找出所有和buddy在同一部門的所有人”
6 列出每個(gè)員工的姓名，工作，部門號(hào)，部門名
select ename,job,dept.deptno,dept.dname from emp,dept where emp.deptno=dept.deptno;
7 列出emp中工作為'CLERK'的員工的姓名，工作，部門號(hào)，部門名
select ename,job,dept.deptno,dept.dname from emp,dept where emp.deptno=dept.deptno where job="CLERK";
8 對(duì)于emp中有管理者的員工，列出姓名，管理者姓名（管理者外鍵為mgr）
select a.deptno,a.ename ,b.ename from emp as a,emp as b where a.mgr is not null and a.mgr=b.ename;
解析：本句可以理解“一個(gè)員工他也是領(lǐng)導(dǎo)，所以emp.ename,emp.mgr 都有值并且有相等的員工”
9 對(duì)于dept表中，列出所有部門名，部門號(hào)，同時(shí)列出各部門工作為'CLERK'的員工名與工作
select a.deptno ,a.dname, b.ename ,b.job from dept as a,emp as b where a.deptno=b.deptno and b.job="clerk";
解析：連表即可
http://blog.csdn.net/shiyuntian_wang/article/details/4636799
建表：
DEPARTMENTS: DEPARTMENT_ID(primary key), DEPARTMENT_NAME, LOCATION
EMPLOYEES: EMPLOYEE_ID(primary key), EMPLOYEE_NAME, EMPLOYEE_JOB, MANAGER, SALARY, DEPARTMENT_ID
- 列出EMPLOYEES表中各部門的部門號(hào)，最高工資，最低工資
select max(SALARY) as 最高工資,min(SALARY) as 最低工資,DEPARTMENT_ID from EMPLOYEES group by DEPARTMENT_ID;
- 列出EMPLOYEES表中各部門EMPLOYEE_JOB為'CLERK'的員工的最低工資，最高工資
select max(SALARY) as 最高工資,min(SALARY) as 最低工資,DEPARTMENT_ID as 部門號(hào) from EMPLOYEES where EMPLOYEE_JOB = 'CLERK' group by DEPARTMENT_ID;
- 對(duì)于EMPLOYEES中最低工資小于1000的部門，列出EMPLOYEE_JOB為'CLERK'的員工的部門號(hào)，最低工資，最高工資
select max(SALARY) as 最高工資,min(SALARY) as 最低工資,DEPARTMENT_ID as 部門號(hào) from EMPLOYEES as b where EMPLOYEE_JOB ='CLERK' and 1000>(select min(SALARY) from EMPLOYEES as a where a.DEPARTMENT_ID = b.DEPARTMENT_ID) group by b.DEPARTMENT_ID
- 根據(jù)部門號(hào)由高而低，工資有低而高列出每個(gè)員工的姓名，部門號(hào)，工資
select DEPARTMENT_ID as 部門號(hào),EMPLOYEE_NAME as 姓名,SALARY as 工資 from EMPLOYEES order by DEPARTMENT_ID desc,SALARY asc
- 列出'張三'所在部門中每個(gè)員工的姓名與部門號(hào)
select EMPLOYEE_NAME,DEPARTMENT_ID from EMPLOYEES where DEPARTMENT_ID = (select DEPARTMENT_ID from EMPLOYEES where EMPLOYEE_NAME = '張三')
- 列出每個(gè)員工的姓名，工作，部門號(hào)，部門名
select EMPLOYEE_NAME,EMPLOYEE_JOB,EMPLOYEES.DEPARTMENT_ID,DEPARTMENTS.DEPARTMENT_NAME from EMPLOYEES,DEPARTMENTS where EMPLOYEES.DEPARTMENT_ID = DEPARTMENTS.DEPARTMENT_ID
- 列出EMPLOYEES中工作為'CLERK'的員工的姓名，工作，部門號(hào)，部門名
select EMPLOYEE_NAME,EMPLOYEE_JOB,DEPARTMENTS.DEPARTMENT_ID,DEPARTMENT_NAME from EMPLOYEES,DEPARTMENTS where DEPARTMENTS.DEPARTMENT_ID = EMPLOYEES.DEPARTMENT_ID and DEPARTMENT_JOB = 'CLERK'
- 對(duì)于EMPLOYEES中有管理者的員工，列出姓名，管理者姓名（管理者外鍵為MANAGER）
select a.EMPLOYEE_NAME as 姓名,b.EMPLOYEE_NAME as 管理者 from EMPLOYEES as a,EMPLOYEES as b where a.MANAGER is not null and a.MANAGER = b.EMPLOYEE_ID
- 對(duì)于DEPARTMENTS表中，列出所有部門名，部門號(hào)，同時(shí)列出各部門工作為'CLERK'的員工名與工作
select DEPARTMENT_NAME as 部門名,DEPARTMENTS.DEPARTMENT_ID as 部門號(hào),EMPLOYEE_NAME as 員工名,EMPLOYEE_JOB as 工作 from DEPARTMENTS,EMPLOYEES where DEPARTMENTS.DEPARTMENT_ID *= EMPLOYEES.DEPARTMENT_ID and EMPLOYEE_JOB = 'CLERK'
- 對(duì)于工資高于本部門平均水平的員工，列出部門號(hào)，姓名，工資，按部門號(hào)排序
select a.DEPARTMENT_ID as 部門號(hào),a.EMPLOYEE_NAME as 姓名,a.SALARY as 工資 from EMPLOYEES as a where a.SALARY>(select avg(SALARY) from EMPLOYEES as b where a.DEPARTMENT_ID = b.DEPARTMENT_ID) order by a.DEPARTMENT_ID
- 對(duì)于EMPLOYEES，列出各個(gè)部門中平均工資高于本部門平均水平的員工數(shù)和部門號(hào)，按部門號(hào)排序
select count(a.SALARY) as 員工數(shù),a.DEPARTMENT_ID as 部門號(hào) from EMPLOYEES as a where a.SALARY>(select avg(SALARY) from EMPLOYEES as b where a.DEPARTMENT_ID = b.DEPARTMENT_ID) group by a.DEPARTMENT_ID order by a.DEPARTMENT_ID
- 對(duì)于EMPLOYEES中工資高于本部門平均水平，人數(shù)多與1人的，列出部門號(hào)，人數(shù)，按部門號(hào)排序
select count(a.EMPLOYEE_ID) as 員工數(shù),a.DEPARTMENT_ID as 部門號(hào),avg(SALARY) as 平均工資 from EMPLOYEES as a where (select count(c.EMPLOYEE_ID) from EMPLOYEES as c where c.DEPARTMENT_ID = a.DEPARTMENT_ID and c.SALARY>(select avg(SALARY) from EMPLOYEES as b where c.DEPARTMENT_ID = b.DEPARTMENT_ID))>1 group by a.DEPARTMENT_ID order by a.DEPARTMENT_ID
- 對(duì)于EMPLOYEES中低于自己工資至少5人的員工，列出其部門號(hào)，姓名，工資，以及工資少于自己的人數(shù)
select a.DEPARTMENT_ID,a.EMPLOYEE_NAME,a.SALARY,(select count(b.EMPLOYEE_NAME) from EMPLOYEES as b where b.SALARY < a.SALARY) as 人數(shù) from EMPLOYEES as a where (select count(b.EMPLOYEE_NAME) from EMPLOYEES as b where b.SALARY<a.SALARY)>5