Pass variable in join query in codeigniter

问题:

I want to pass the variable $mid in join query at join('movie_genre','movie_genre.movie_id=$mid'); it does not work.

$this->db->select('movie_details.movie_id,movie_details.title,movie_details.producer,movie_details.director,movie_details.writer,
       GROUP_CONCAT(movie_genre.genre) As genre, movie_genre.movie_id');
        $this->db->from('movie_details');
        $this->db->join('movie_genre','movie_genre.movie_id=$mid');

        $this->db->group_by('movie_genre.movie_id'); 

        $result=$this->db->get();
        return $result->row_array();

回答1:

Try this:

$this->db->join('movie_genre','movie_genre.movie_id='.$mid);

Use echo $this->db->last_query(); for printing out the last query.

Note: $mid should be something like table_name.column_name