显示作者姓名，书名为谁写的多本书籍

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

这些作者还可以使用内部联接，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 

anfd您可以获取所有的书在同一行中使用group_concat

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