Mysql trigger problem, I want to delete the content of an article and the comments about this article in another table will also be deleted at the same time. How to write this?

delimiter //

create trigger tr_cno before delete on wenzhnag for each row

begin

delete from choose where content= old.content;

end;

//

delimiter ;

delete from pinglun where content='';

i It was originally written like this but I keep getting errors

Please tell me how to write this