串联 - 名字和姓氏相同的列 (Oracle SQL)

Question

对 Oracle SQL 来说是全新的，话虽如此：

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撰写的书籍数量（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

连接似乎不起作用，并且整个查询存在问题。

以下是相关的表格：

图书：ISBN、TITLE

作者：AUTHORID、LNAME、FNAME

图书作者：ISBN、AUTHORID

即使我尝试只使用 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