create database egdb1 charset=utf8;
show databases;
use egdb1;
create table bookes (
    id int primary key auto_increment,
    bname varchar(50) not null,
    author varchar(30) not null default '佚名',
    press varchar(128),
    price float(7,2) not null default 0.00,
    comment text
)charset=utf8;
alter table bookes change price price decimal(7,2) not null default 0.00;
desc bookes;

insert into bookes(bname, author, press, price, comment)
values
('边城','沈从文','机械工业出版社',36,'小城故事多'),
('骆驼祥子','老舍','机械工业出版社',43,'你是祥子么'),
('茶馆','老舍','中国文学出版社',55,'老北京'),
('呐喊','鲁迅','人民教育出版社',71,'最后的声音'),
('朝花夕拾','鲁迅','中国文学出版社',53,'好时光'),
('围城','钱钟书','中国文学出版社',44,'你心中的围城是什么');

select *from bookes;

insert into bookes(bname, author, press, price)
values
('林家铺子','茅盾','机械工业出版社',51),
('子夜','茅盾','人民教育出版社',47);

select bname from bookes where press='人民教育出版社';
select bname from bookes where author='老舍' and press='中国文学出版社';
select bname,price from bookes where price>60;
update  bookes set  price=45 where bname='呐喊';
alter table bookes add column publish_date date after price;
update bookes set publish_date='2018-10-01' where author='老舍';
update bookes set price=price+5 where author='鲁迅';
delete from bookes where price>70 or price<40;