join - 串联 - 名字和姓氏相同的列 (Oracle SQL)

Question

对 Oracle SQL 完全陌生，话虽这么说:

尝试在与“作者”相同的列中显示作者的名字和姓氏以及该作者所写的书籍数量(结果按作者名字升序排列)。

SELECT AUTHOR.FNAME || ' ' || AUTHOR.LNAME AS "Author",
COUNT(BOOKAUTHOR.AUTHORID) AS "Books written"
FROM BOOKS
INNER JOIN BOOKAUTHOR ON BOOKS.ISBN = BOOKAUTHOR.ISBN
INNER JOIN AUTHOR ON BOOKAUTHOR.AuthorID = AUTHOR.AuthorID
ORDER BY AUTHOR.FNAME ASC

串联似乎不起作用，整个查询有问题。

以下是相关的表格:

书籍:ISBN、TITLE

作者:AUTHORID、LNAME、FNAME

BookAuthor: ISBN, AUTHORID

即使我尝试仅使用 SELECT 和 FROM 进行简单的连接，它也不会显示任何结果。

例如:

SELECT FNAME || ' ' || LNAME "AUTHOR NAME"
FROM AUTHOR

Answer 1

试试这个:

SELECT CONCAT(CONCAT(AUTHOR.FNAME, ' '),
      AUTHOR.LNAME) AS "AUTHOR" 
COUNT(BOOKAUTHOR.AUTHORID) AS "Books written"
FROM BOOKS
INNER JOIN BOOKAUTHOR ON BOOKS.ISBN = BOOKAUTHOR.ISBN
INNER JOIN AUTHOR ON BOOKAUTHOR.AuthorID = AUTHOR.AuthorID
ORDER BY AUTHOR.FNAME ASC