简单的MySql SELECT

Question

我有一个表为工作日分配工作日ID。

Table: workdays  Table: jobs 
+------+-------+  +------+-----------+ 
| id | days |  | id | jobs  | 
+------+-------+  +------+-----------+ 
| 1 | mon |  | 1 | cleaning | 
| 1 | tue |  | 2 | cooking | 
| 2 | sat |  | 3 | driving | 
| 3 | mon |  | 4 | cleaning | 
| 3 | tue |  | 5 | cooking | 
| 3 | sat |  +------+-----------+ 
| 4 | wed | 
| 4 | mon | 
| 5 | tue | 
+------+-------+ 

这是我用它来选择的人谁在任何的日工作的ID我指定（比如周一和周二）查询：

SELECT * FROM workdays WHERE days IN ('mon', 'tue') 

现在，我想选择那些在我指定的所有日子里工作的人。我怎样才能做到这一点？

编辑：增加第二个表。

Answer 1

假设days对于每个id都是唯一的。

SELECT id 
FROM workdays 
WHERE days IN ('mon', 'tue') 
GROUP BY id 
HAVING COUNT(*) = 2 

否则，你需要有DISTINCT在HAVING条款来算唯一的值。

HAVING COUNT(DISTINCT days) = 2