$stmt = $dbConn->prepare("SELECT * FROM
            (
            SELECT subject.id as 'SubjectID', subject.title, subject.menu_image, video.id as 'VideoID' FROM video LEFT JOIN subject ON video.subject_id = subject.id WHERE video.is_active = 1 AND video.activation_date <= CURDATE() ORDER BY subject.id, video.title
            ) as tmp
            group by SubjectID");