如何在codeigniter 3中创建两个join ?

Question

我有3个表:

**Clients**
id | names 
1  | Paul
2  | Jack
**Course** 
id | names 
1  | Med 
2  | Nur 
**Class** 
class_id | clients_id  | course_id 
1        |   1         | 1
2        |   2         | 1
3        |   1         | 2 
**I want to show this:** 
**Result**
class_id |clients_names | courses_names
1        | Paul         | Med
2        | Jack         | Med 
3        | Paul         | Nur

我怎么能得到这个结果?我已经知道如何使一个连接，但是这个双连接快把我逼疯了。

呢。

Answer 1

Try;

select 
    c.class_id, cl.names clients_names, co.names courses_names
from Class c
join Clients cl on cl.id = c.clients_id
join Course co on co.id = c.course_id 

Answer 2

您可以简单地使用CI活动记录

$this->db->select('cla.class_id,cli.names as clients_names, co.names as courses_names',false);
$this->db->from('Class cla');
$this->db->join("Clients cli","cla.clients_id = cli.id");
$this->db->join("Course co","cla.course_id = co.id");