[英]Return Authors by latest published book + Authors with no published books
我有兩個表:
•表1: Books
•表2: Authors
我有以下查詢:(此查詢返回具有書名和出版日期的所有作者)
SELECT Authors.AuthorName, Books.BookTitle, Books.DatePublished, Books.Author
FROM Authors LEFT OUTER JOIN Books ON Authors.AuthorID = Books.Author
問題:!!
我想歸還所有作者(既有出版過的書籍,也有沒有出版過的書籍。
條件(擁有書籍的作者。僅返回最新出版的書籍)
我可以通過以下查詢獲取最新出版的書:
SELECT a.*
FROM [Books] a left outer join Books b on a.Author = b.author and
a.DatePublished < b.DatePublished where b.ISDN is null
問題:如何合並這兩個查詢,以返回所有作者+最新出版的書的作者?
請試試:
SELECT DISTINCT
AuthorName,
BookTitle,
DatePublished,
Author
FROM(
SELECT
Authors.AuthorName,
Books.BookTitle,
Books.DatePublished,
Books.Author,
ROW_NUMBER() over (partition by Authors.AuthorID order by DatePublished desc) Rnum
FROM Authors LEFT OUTER JOIN Books ON Authors.AuthorID = Books.Author
)x WHERE Rnum=1
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