sql语句写出来的代码运行以后为什么出来好多重复的数据??

2025-03-24 16:40:22
推荐回答(1个)
回答1:

SELECT distinct Book.BookCode, Book.Title
FROM Branch, Copy, Book, Publisher
WHERE Branch.BranchNum=Copy.BranchNum
And Copy.BookCode=Book.BookCode 
And Book.PublisherCode=Publisher.PublisherCode
And (Publisher.PublisherName='Vintage Books' Or Branch.BranchName='ABC Brentwood');