create table madou_video_info ( id bigserial primary key not null, title varchar(255) not null, classify varchar(255) not null, cover_url varchar(255), m3u8_url varchar(255) ); create table classify_info ( id bigserial primary key not null, name varchar(255) not null, url varchar(255) not null, page_size int not null ); select sum(page_size) * 18 / 1024 / 2 from classify_info;