需要帮助，我有三个表“用户”、“朋友”和“状态”我很难按条件加入到“朋友表”中
users table
id | name | usercode
--------------------
1 | david | 2WM
2 | Samme | E5N
3 | Awudu | C0Q
4 | John | VX6
5 | Jerem | FG3
Friends Table
id | actor | target
--------------------
1 | E5N | FG3
2 | 2WM | VX6
3 | FG3 | 2WM
4 | C0Q | VX6
5 | FG3 | VX6
Status Table
id | usercode | status
--------------------
1 | E5N | I am busy now
2 | 2WM | The night is falling too fast
3 | FG3 | Good day
4 | C0Q | Very tired, trust me
5 | VX6 | YeLLLLOOO
我想得到的是“用户表”中的所有“用户”和“状态表”中相应的“状态”，其中“FG3”是“目标”或“FG3”是“朋友表”中的“参与者”
所以结果会是
id | name | usercode | actor | target | status
------------------------------------------------
2 | Samme | E5N | E5N | FG3 | I am busy now
1 | david | 2WM | FG3 | 2WM | The night is falling too fast
5 | John | VX6 | FG3 | VX6 | YeLLLLOOO
请帮忙，谢谢。
最佳答案
SELECT u.name,
u.usercode,
f.actor,
f.target,
s.status
FROM Users u,
Friends f,
Status s
WHERE ((u.usercode = f.actor AND 'FG3' = f.target)
OR (u.usercode = f.target AND 'FG3' = f.actor))
AND s.usercode = u.usercode
关于php - 在三个表上的MySQL查询，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/27955280/