表 course

mysql> select * from course;

+----+-------------+

| id | course_name |

+----+-------------+

| 1 | Java |

| 2 | MySQL |

| 3 | Python |

| 4 | Go |

| 5 | C++ |

+----+-------------+

5 rows in set (0.00 sec)

表students

mysql> select * from students;

+------+--------+------+------+--------+-----------+

| id | name | age | sex | height | course_id |

+------+--------+------+------+--------+-----------+

| 1 | Danny | 25 | 1 | 160 | 1 |

| 2 | Green | 23 | 1 | 158 | 2 |

| 3 | Henry | 23 | 0 | 185 | 1 |

| 4 | Jane | 22 | 1 | 162 | 3 |

| 5 | Jim | 24 | 0 | 175 | 2 |

| 6 | John | 21 | 0 | 172 | 4 |

| 7 | Lily | 22 | 1 | 165 | 4 |

| 8 | Susan | 23 | 1 | 170 | 5 |

| 9 | Thomas | 22 | 0 | 178 | 5 |

| 10 | Tom | 23 | 0 | 165 | 5 |

+------+--------+------+------+--------+-----------+

10 rows in set (0.00 sec)

表 stusex

mysql> select * from stusex;

+------+------+

| id | sex |

+------+------+

| 0 | 女 |

| 1 | 男 |

+------+------+

2 rows in set (0.00 sec)

做连接

mysql> select s.id,s.name,s.age, d.sex,c.course_name from students s,stusex d,course c where s.sex = d.id and s.course_id = c.id;

+------+--------+------+------+-------------+

| id | name | age | sex | course_name |

+------+--------+------+------+-------------+

| 1 | Danny | 25 | 男 | Java |

| 2 | Green | 23 | 男 | MySQL |

| 3 | Henry | 23 | 女 | Java |

| 4 | Jane | 22 | 男 | Python |

| 5 | Jim | 24 | 女 | MySQL |

| 6 | John | 21 | 女 | Go |

| 7 | Lily | 22 | 男 | Go |

| 8 | Susan | 23 | 男 | C++ |

| 9 | Thomas | 22 | 女 | C++ |

| 10 | Tom | 23 | 女 | C++ |

+------+--------+------+------+-------------+

10 rows in set (0.00 sec)

标签：22,多个,23,连接,course,MySQL,sex,id,name

来源： https://www.cnblogs.com/conpi/p/14352949.html