Question

我一直试图将此查询限制为具有多个作者的书籍（应该是四个），但我无法弄明白。有人可以帮忙吗？

这是我的代码：

SELECT title, COUNT(authorid) AS "Number of Authors"
FROM book_author, books, publisher
    WHERE publisher.pubid(+) = books.pubid
        AND books.bookid(+) = book_author.bookid
            GROUP BY title;

结果如下：

    SQL> SELECT title, COUNT(authorid) AS "Number of Authors"
  2   FROM book_author, books, publisher
  3    WHERE publisher.pubid(+) = books.pubid
  4     AND books.bookid(+) = book_author.bookid
  5      GROUP BY title;

TITLE                          Number of Authors
------------------------------ -----------------
DATABASE IMPLEMENTATION                        3
PAINLESS CHILD-REARING                         3
HOW TO GET FASTER PIZZA                        1
SHORTEST POEMS                                 1
BIG BEAR AND LITTLE DOVE                       1
BODYBUILD IN 10 MINUTES A DAY                  2
HOLY GRAIL OF ORACLE                           1
HANDCRANKED COMPUTERS                          2
HOW TO MANAGE THE MANAGER                      1
COOKING WITH MUSHROOMS                         1
BUILDING A CAR WITH TOOTHPICKS                 1
E-BUSINESS THE EASY WAY                        1
REVENGE OF MICKEY                              1
THE WOK WAY TO COOK                            1

14 rows selected.

非常感谢任何帮助。

Answer 1

HAVING子句将过滤聚合值：

SELECT title, COUNT(authorid) AS "Number of Authors"
FROM book_author, books, publisher
WHERE publisher.pubid(+) = books.pubid
  AND books.bookid(+) = book_author.bookid
GROUP BY title
HAVING COUNT(authorid) > 1

如何将此查询限制为仅包含多个作者的书籍？

1 个答案: