mysql - how can i retrieve the child table data from master table in a string value -

this master table structure

create table if not exists `gf_film` (    `film_id` bigint(20) not null auto_increment,    `user_id` int(20) not null,    `film_name` varchar(100) default null,    `film_cat` varchar(30) character set latin1 default null,    `film_plot` longtext,    `film_release_date` date default null,    `film_post_date` date default null,    `film_type` enum('movie','tv') character set latin1 default 'movie',    `film_feature` enum('y','n') character set latin1 not null default 'n',    `film_status` enum('active','inactive') character set latin1 not null default 'active',    `film_modify` timestamp not null default current_timestamp on update current_timestamp,    `film_link_value` varchar(200) not null,    `film_post_link` varchar(255) not null,    primary key (`film_id`) ) engine=myisam  default charset=utf8 auto_increment=21435 ; 

this child table through map between above gf_film table , lowest gf_actor table

create table if not exists `gf_film_actor` (    `film_id` int(20) not null,    `actor_id` int(20) not null,    key `film_id` (`film_id`)  ) engine=myisam default charset=latin1; 

this table have reitrieve actor name

create table if not exists `gf_actor` (    `actor_id` bigint(20) not null auto_increment,    `actor_name` varchar(100) default null,    `actor_desc` longtext character set latin1,    primary key (`actor_id`),    unique key `actor_name` (`actor_name`) ) engine=myisam  default charset=utf8 auto_increment=60963 ; 

and schema gf_film_poster

create table if not exists `gf_film_poster` (    `film_id` int(20) not null,    `website_poster_url` varchar(255) default null,    `original_poster_url` varchar(255) default null,    `default_poster_url` varchar(255) default 'noposter.gif',    unique key `film_id` (`film_id`)  ) engine=myisam default charset=latin1; 

after execute query

select gf_film.film_id                                 ,        film_name                                       ,        date_format(film_release_date,'%d') date     ,        date_format(film_release_date,'%m') month_ori,        date_format(film_release_date,'%m') month    ,        date_format(film_release_date,'%y') year     ,        film_release_date                               ,        film_feature                                    ,        film_modify                                     ,        film_post_link                                  ,        website_poster_url   gf_film        left join gf_film_poster        on     gf_film.film_id=gf_film_poster.film_id 

i getting these results database

film_id,film_name,date,month_ori,month,year,film_release_date,  film_feature,film_modify,film_post_link,website_poster_url 

so need column contain actors name , actor_id in 1 row related each movies joing above query gf_actor , gf_film_actor

select   gf_film.film_id                                 ,          film_name                                       ,          date_format(film_release_date,'%d') date     ,          date_format(film_release_date,'%m') month_ori,          date_format(film_release_date,'%m') month    ,          date_format(film_release_date,'%y') year     ,          film_release_date                               ,          film_feature                                    ,          film_modify                                     ,          film_post_link                                  ,          website_poster_url                              ,          group_concat(gf_actor.actor_name) actors     gf_film          left join gf_film_poster          on       gf_film.film_id=gf_film_poster.film_id          left join gf_film_actor          on       gf_film_actor.film_id = gf_film.film_id          left join gf_actor          on       gf_film_actor.actor_id = gf_actor.actor_id group gf_film.film_id