Question

CREATE TABLE Book_Master(
Book_code NUMBER(10) PRIMARY KEY,
Book_name VARCHAR2(50) NOT NULL,
Book_pub_year NUMBER,
Book_pub_author VARCHAR2 (50) NOT NULL);

INSERT INTO book_master VALUES(10000001,'Let Us C++',2000,'Yashavant Kanetkar');

INSERT INTO book_master VALUES(10000002,'Mastersing VC++',2005,'P.J Allen');

INSERT INTO book_master VALUES(10000003,'JAVA Complete Reference',2004,'H.Schild');

INSERT INTO book_master VALUES(10000004,'J2EE Complete Reference',2000,'H. Schild');

INSERT INTO book_master VALUES(10000005,'Relational DBMS',2000,'B.C. Desai');

INSERT INTO book_master VALUES(10000006,'Let Us C',2000, 'Yashavant Kanetkar');

INSERT INTO book_master VALUES(10000007,'Intoduction To Algorithams',2001,'Cormen');

INSERT INTO book_master VALUES(10000008,'Computer Networks',2000,'Tanenbaum');

INSERT INTO book_master VALUES(10000009,'Introduction to O/S',2001,'Millan');

Answer 1

select Book_pub_author, Book_name 
  from book_master 
 where Book_pub_author in ( select Book_pub_author 
                              from book_master 
                             group by Book_pub_author 
                            having count(1)>1 )
 order by Book_pub_author, Book_name

Answer 2

您也可以使用内部联接而不是IN子句

Select Book_pub_author
    , Book_name 
from book_master b 
INNER JOIN (
  select Book_pub_author 
  from book_master 
  group by Book_pub_author 
  having count(1)>1
) t on t.Book_pub_author = b.Book_pub_author

你可以使用group_concat

获取同一行中的所有书籍

Select Book_pub_author
    , group_concat(Book_name )
from book_master b 
INNER JOIN (
  select Book_pub_author 
  from book_master 
  group by Book_pub_author 
  having count(1)>1
) t on t.Book_pub_author = b.Book_pub_author
group by Book_pub_author

显示作者姓名，书名为编写多本书的作者

2 个答案: