mysql - 从两个表中获取数据

Question

我正在使用rails3。我有两张桌子user_shift，另一张是shift桌子。我想要特定用户的当前班次。user_shift表字段是

`id`, 
`from`, 
`to`, 
`shift_id`, 
`user_id`, 
`created_at`, 
`updated_at` 

并且在shift表字段中是

`id`, 
`start_time`, 
`end_time`, 
description`, 
`created_at`, 
`updated_at` . 

Answer 1

MySQL 连接是最好的解决方案。

例子

SELECT * FROM shift LEFT JOIN user_shift ON shift.id = user_shift.shift_id

随用户移动

SELECT * FROM shift LEFT JOIN user_shift ON shift.id = user_shift.shift_id WHERE user_shift.user_id = LOGGEDINUSERID

Answer 2

试试这个查询

SELECT us.id, s.start_time, s.end_time 
FROM user_shift us, shift s
WHERE us.shift_id = s.id AND us.id=?;