我在mysql中遇到了一些表。真的不知道如何从三个表中加入信息。非常感谢有人能帮助我。谢谢。
这就是我所拥有的:
Table1.Users
+----+--------+--------------+
| id | name | lastname |
+----+--------+--------------+
| 1 | Peter | Elk |
| 2 | Amy | Lee |
| 3 | James | Ride |
| 4 | Andrea | Thompson |
+----+--------+--------------+
Table2.Projects
+-----+-------------+
| id | name |
+-----+-------------+
| 13 | Lmental |
| 26 | Comunica |
| 28 | Ecobalear |
| 49 | Puigpunyent |
+-----+-------------+
Table3.Users_Projects
+----------+-------------+
| id_users | id_projects |
+----------+-------------+
| 1 | 13 |
| 1 | 28 |
| 2 | 13 |
| 2 | 28 |
| 2 | 49 |
| 3 | 28 |
| 3 | 49 |
| 4 | 49 |
+----------+-------------+
我想打印这样的东西:
+--------+--------------+----------------------------------+
| name | lastname | project |
+--------+--------------+----------------------------------+
| Peter | Elk | Lmental,Ecobalear |
| Amy | Lee | Lmental,Ecobalear, Puigpunyent |
| James | Ride | Ecobalear,Puigounyent |
| Andrea | Thompson | Puigpunyent |
+--------+--------------+----------------------------------+
答案 0 :(得分:2)
像...一样的东西。
SELECT Users.name, Users.lastname, Projects.name
FROM (Users, Projects, Users_Projects)
WHERE Users_Projects.id_users=Users.id AND Users_Projects.id_projects=Projects.id
ORDER BY ...
...每行输出一个用户/项目,然后你必须用你选择的语言进行操作。
尝试在SQL中执行连接等可能导致非常可怕的查询。