BookStore数据库中有图书表Book(BookCode,BookName,Author,PublisherCode,PublishTime,PublishTime是datetime类型。查询Book表中的图书类别(BookSort),要求每个类别只显示一次。SQL语句:SELECT()BookSort FROM Book
A、DISTINCT
B、ONLY
C、ONE
D、PERCENT
A、DISTINCT
B、ONLY
C、ONE
D、PERCENT
A、增加一个表:借阅表(读者编号、图书编号) B、增加一个表:读者-作者表(读者编号、作者编号) C、增加一个表:借阅表(读者编号、图书编号、作者编号) D、增加两个表:借阅表(读者编号、图书编号),读者-作者表(读者编号、作者编号)
A、Price=Price*0.9,Discount=0.8 B、Price=Price*(1-10%),Discount=0.8 C、Price=0.9,Discount=0.8 D、Discount=0.8,Price=Price*0.9
A、DELET Epublisher WHERE Publisher=‘群众出版社’ B、DELETE FROM Publisher WHERE Publisher=‘群众出版社’ C、DELETE FROM Publisher WHERE Publisher=群众出版社 D、DELETE Publisher WHERE Publisher=群众出版社
A、* B、CustomerCode,Name,Hometown,Sex,Email,Telephone,LoginTime,PassWord C、CustomerCode,Hometown,Telephone,Name,Sex,Email,LoginTime,PassWord D、CustomerCode~PassWord