串联 - 名字和姓同列（甲骨文SQL）

Question

完全陌生的Oracle SQL，他这样说：

试图首先显示作者的名和姓在同一列的“作者”与一起该作者编写的书籍数量（按作者名字的升序排列）。

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 

并发似乎没有工作，并与整体查询有问题。

下面是与表：

书籍：ISBN，书名

作者：AUTHORID，LNAME，FNAME

BOOKAUTHOR：ISBN，AUTHORID

即使当我尝试使用SELECT和FROM做一个简单的连接时，它也不会显示一个y结果。

例如像：

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