A.數(shù)據(jù)庫管理系統(tǒng)/用戶/操作系統(tǒng) B.數(shù)據(jù)庫管理系統(tǒng)/硬件/操作系統(tǒng) C.數(shù)據(jù)庫管理系統(tǒng)/操作系統(tǒng)/用戶 D.數(shù)據(jù)庫管理系統(tǒng)/用戶/軟件
A.select staffno from staff where E_mail=NULL B.select staffno from staff where E_mail NULL C.select staffno from staff where E_mail is NULL D.select staffno from staff where E_mail is not NULL
A.SELECT price FROM book WHERE book_name=“數(shù)據(jù)庫*” B.SELECT price FROM book WHERE book_name LIKE“數(shù)據(jù)庫*” C.SELECT price FROM book WHERE book_name=“數(shù)據(jù)庫%” D.SELECT price FROM book WHERE book_name LIKE“數(shù)據(jù)庫%”