Assignment Operator := breaks the query builder

I am try to create this query using the query builder

Code:

SELECT *, (@no:=@no+1) AS no FROM user WHERE user.deleted = 0

 but by using the Codeigniter 4 query builder but it returns the query as 

Code:

SELECT *, (@no:=@no+1) AS no FROM `user` WHERE `user`.`deleted` = :user.deleted:

This is the code I used to this

Code:

$this->builder = $this->db->table('user');
$this->builder->select('*, (@no:=@no+1) AS no');
$this->builder->where("user.deleted", 0);