-- 部門表
create table dept (
id int primary key primary key, -- 部門id
dname varchar(50), -- 部門名稱
loc varchar(50) -- 部門所在地);
-- 新增4個部門
insert into dept(id,dname,loc) values
(10,'教研部','北京'
),(20,'學工部','上海'
),(30,'銷售部','廣州'
),(40,'財務部','深圳');
-- 職務表，職務名稱，職務描述
create table job (
id int primary key,
jname varchar(20),
description varchar(50));
-- 新增4個職務
insert into job (id, jname, description) values
(1, '董事長', '管理整個公司，接單'
),(2, '經理', '管理部門員工'
),(3, '銷售員', '向客人推銷產品'
),(4, '文員', '使用辦公軟體');
-- 員工表
create table emp (
id int primary key, -- 員工id
ename varchar(50), -- 員工姓名
job_id int, -- 職務id
mgr int , -- 上級領導
joindate date, -- 入職日期
salary decimal(7,2), -- 工資
bonus decimal(7,2), -- 獎金
dept_id int, -- 所在部門編號
constraint emp_jobid_ref_job_id_fk foreign key (job_id) references job (id),
constraint emp_deptid_ref_dept_id_fk foreign key (dept_id) references dept (id));
-- 新增員工
insert into emp(id,ename,job_id,mgr,joindate,salary,bonus,dept_id) values
(1001,'孫悟空',4,1004,'2000-12-17','8000.00',null,20),
(1002,'盧俊義',3,1006,'2001-02-20','16000.00','3000.00',30),
(1003,'林沖',3,1006,'2001-02-22','12500.00','5000.00',30),
(1004,'唐僧',2,1009,'2001-04-02','29750.00',null,20),
(1005,'李逵',4,1006,'2001-09-28','12500.00','14000.00',30),
(1006,'宋江',2,1009,'2001-05-01','28500.00',null,30),
(1007,'劉備',2,1009,'2001-09-01','24500.00',null,10),
(1008,'豬八戒',4,1004,'2007-04-19','30000.00',null,20),
(1009,'羅貫中',1,null,'2001-11-17','50000.00',null,10),
(1010,'吳用',3,1006,'2001-09-08','15000.00','0.00',30),
(1011,'沙僧',4,1004,'2007-05-23','11000.00',null,20),
(1012,'李逵',4,1006,'2001-12-03','9500.00',null,30),
(1013,'小白龍',4,1004,'2001-12-03','30000.00',null,20),
(1014,'關羽',4,1007,'2002-01-23','13000.00',null,10)
;-- 工資等級表
create table salarygrade (
grade int primary key, -- 級別
losalary int, -- 最低工資
hisalary int -- 最高工資);
-- 新增5個工資等級
insert into salarygrade(grade,losalary,hisalary) values
(1,7000,12000),
(2,12010,14000),
(3,14010,20000),
(4,20010,30000),
(5,30010,99990)
;
– 1.查詢所有員工資訊。查詢員工編號，員工姓名，工資，職務名稱，職務描述
/*分析：員工編號，員工姓名，工資-查詢emp ,職務名稱，職務描述-查詢job表
查詢的條件 emp.job_id =job.id
*/
select
t1.`id`
, t1.`ename`
, t1.`salary`
, t2.`jname`
, t2.`description`
from
emp t1,job t2
where
t1.`job_id`
=t2.`id`
;
/*分析：
1.員工編號，員工姓名，工資emp，職務名稱，職務描述job，部門名稱位置dept
emp.job_id =job.id and emp.dept_id =dept.id
*/
select
t1.`id`
, t1.`ename`
, t1.`salary`
, t2.`jname`
, t2.`description`
, t3.`dname`
, t3.`loc`
from
emp t1,job t2,dept t3
where
t1.`job_id`
=t2.`id`
and t1.`dept_id`
=t3.`id`
;
/*分析：
員工姓名，工資emp,工資等級salarygrade
emp.salarygrade between losalary and hisalary
*/
select
t1.`ename`
, t1.`salary`
, t2.*
from
emp t1, salarygrade t2
where
t1.`salary`
between t2.`losalary`
and t2.`hisalary`
;
/*分析：員工姓名，工資emp，職務名稱，職務描述job,
部門名稱，部門位置dept 工資等級salarygrade
條件：emp.job_id =job.id and emp.dept_id =dept.id and emp.salarygrade between losalary and hisalary
*/
select
t1.`ename`
, t1.`salary`
, t2.`jname`
, t2.`description`
, t3.`dname`
, t3.`loc`
, t4.*
from
emp t1 ,job t2,dept t3,salarygrade t4
where
t1.`job_id`
=t2.`id`
and t1.`dept_id`
=t3.`id`
and t1.`salary`
between t4.`losalary`
and t4.`hisalary`
;
/*使用分組查詢，按照emp.dept_id完成分組，查詢人數
使用子查詢上一步的結果和dept表進行關聯查詢
*/
select
t1.`id`
,t1.`dname`
,t1.`loc`
,t2.total
from
dept t1,
(select
dept_id,count(id)total
from
empgroup by dept_id)t2
where t1.`id`
= t2.dept_id;
/*分析：姓名emp 直接上級名字emp
emp表的id和mgr自關聯
條件emp.id =emp.mgr
需要查詢左表的所有資料和交集資料
使用左外連線查詢
*/
select
t1.`ename`
, t1.`mgr`
, t2.`id`
, t2.`ename`
from emp t1
left join emp t2
on t1.`mgr`
=t2.`id`
;
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