$query = $this->db->query("Set @videos.video_id:=0");
$query = $this->db->query("Select
@videos.video_id := @videos.video_id+1 AS sira,videos.category_id,videos.season_id,videos.sef_uri
FROM videos
INNER JOIN categories ON videos.category_id=categories.cat_id WHERE videos.sef_uri='$video_sef_uri' and categories.sef_uri='$cat_sef_uri'
ORDER BY videos.sef_uri+0 asc");