Multi Query Problems in Codeigniter 3

I want to ask about the CI3 problem. 

Why in Codeigniter 3 can't run multi query with select statement
I tried to  

Code:

var_dump($get) 

but the result is boolean.
This is my code : 

PHP Code:

$get = $this->db->query("
            insert tblmaster values('namefield','cityfield');
            select * from tblmaster;
            ");

var_dump($get);