Yii2: How to do a inner join of three tables? - join

Question

I have a many-to-many relationship so I have three tables (administrators, offices and the intermediate table):
I need to do a very simple innerjoin of the three tables to show lastnames and their offices with Active Record. I tried but I couldn't.
This is what I tried:
$admins = Admins::find()
->joinWith(Oficinas::tableName())
->all();
echo '<pre>';
print_r($admins);
echo '</pre>';
die();
Also I would like to know how to show the SQL query so it can help me to find a solution.

Answer 1

You need to specify the relation name for joinWith() rather than table names. Since there isn't any info on the relation names I will use simple innerJoin using table names as per your requirements to display the last name and the office name for the admins.
Admins::find()
->alias('a')
->select('a.lastnameadm, o.nombreofi')
->innerJoin('admin_oficinas ao','ao.idadm = a.idadm')
->innerJoin('oficinas o','o.idofi = ao.idofi')
->all();

Answer 2

Try this:
TABLE_NAME_1::find()
->join('inner join',
'table_name_2',
'table_name_2.column = table_name_1.column'
);
->join('inner join',
'table_name_3',
'table_name_3.column = table_name_2.column'
)->all();
but if you can also use Via like the following example:
public function getClassschedule()
{
return $this->hasOne(TABLE_NAME_2::className(), ['table_name_1.column' => 'table_name_2.column'])
->via('tableName3');
}
when excuded, the results should be obtained like the previous example. so there's no need to repeated relations. full documentation can be seen here :
https://www.yiiframework.com/doc/guide/2.0/en/db-active-record