多表查询：
http://www.cnblogs.com/linhaifeng/articles/7267596.html
1.多表连接查询
2.符合条件连接查询
3.子查询
一、准备表记录
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1 # 建表
2 create table department(
3 id int,
4 name varchar(20)
5 );
6 create table employee(
7 id int primary key auto_increment,
8 name varchar(20),
9 sex enum('male','female') not null default 'male',
10 age int,
11 dep_id int
12 );
13 # 插入数据
14 insert into department values
15 (200,'技术'),
16 (201,'人力资源'),
17 (202,'销售'),
18 (203,'运营');
19 insert into employee(name,sex,age,dep_id) values
20 ('egon','male',18,200),
21 ('alex','female',48,201),
22 ('wupeiqi','male',38,201),
23 ('yuanhao','female',28,202),
24 ('liwenzhou','male',18,200),
25 ('jingliyang','female',18,204);
26 # 查看表结构和数据
27 mysql> desc department;
28 +-------+-------------+------+-----+---------+-------+
29 | Field | Type | Null | Key | Default | Extra |
30 +-------+-------------+------+-----+---------+-------+
31 | id | int(11) | YES | | NULL | |
32 | name | varchar(20) | YES | | NULL | |
33 +-------+-------------+------+-----+---------+-------+
34 2 rows in set (0.00 sec)
35
36 mysql> desc employee;
37 +--------+-----------------------+------+-----+---------+----------------+
38 | Field | Type | Null | Key | Default | Extra |
39 +--------+-----------------------+------+-----+---------+----------------+
40 | id | int(11) | NO | PRI | NULL | auto_increment |
41 | name | varchar(20) | YES | | NULL | |
42 | sex | enum('male','female') | NO | | male | |
43 | age | int(11) | YES | | NULL | |
44 | dep_id | int(11) | YES | | NULL | |
45 +--------+-----------------------+------+-----+---------+----------------+
46 5 rows in set (0.00 sec)
47
48 mysql> select * from department;
49 +------+--------------+
50 | id | name |
51 +------+--------------+
52 | 200 | 技术 |
53 | 201 | 人力资源 |
54 | 202 | 销售 |
55 | 203 | 运营 |
56 +------+--------------+
57 4 rows in set (0.00 sec)
58
59 mysql> select * from employee;
60 +----+------------+--------+------+--------+
61 | id | name | sex | age | dep_id |
62 +----+------------+--------+------+--------+
63 | 1 | egon | male | 18 | 200 |
64 | 2 | alex | female | 48 | 201 |
65 | 3 | wupeiqi | male | 38 | 201 |
66 | 4 | yuanhao | female | 28 | 202 |
67 | 5 | liwenzhou | male | 18 | 200 |
68 | 6 | jingliyang | female | 18 | 204 |
69 +----+------------+--------+------+--------+
70 6 rows in set (0.00 sec)
建表 插入数据