create table actor( actor_id smallint not null primary key , first_name varchar(45) not null , last_name varchar(45) not null , last_update date not null )
create table if not exists actor( actor_id smallint(5) not null comment '主键id', first_name varchar(45) not null comment '名字', last_name varchar(45) not null comment '姓氏', last_update date not null comment '日期', primary key (actor_id));
create table if not exists actor( actor_id smallint(5) not null primary key comment'主键id', first_name varchar(45) not null comment'名字', last_name varchar(45) not null comment '姓氏',
create table actor( actor_id smallint(5) not null primary key COMMENT'主键id', first_name varchar(45) not null COMMENT'名字', first_name varchar(45) not null COMMENT'姓氏', last_update date not null COMMENT'日期')