setting mysql user-defined variable with query-builder

Question

I have an issue with setting mysql user-defined variables with codeigniter. How am I able to use SET with CI query builder?

SET @weekVideoCount := (SELECT COUNT(*) FROM videos v );

SELECT @weekVideoCount;

When I execute this Query on Sqlyog the result will be successfully shown but if I call this Query in the model like this

function getWeeklyUserData(){
        $query= $this->db->query("SET @weekVideoCount := (SELECT COUNT(*) FROM videos v);
                                SELECT @weekVideoCount;
                                ");
        return $query->result();
    }

the error has generated

Answer 1

Try separate the query

 $this->db->query("SET @weekVideoCount := (SELECT COUNT(*) FROM videos v)");
 $query= $this->db->query("SELECT @weekVideoCount");

Answer 2

you should know $this->db->query() execute only one sql statement just like mysql_query.