How to find if same book is purchased in two years.

Question

Hi all,
I need to find out which books are sold in both 2005 and 2007 only.
create table books
(book_id number,
name varchar2(20),
purchase_date date);
begin
insert into books values (1,'Oracle','22-jan-01');
insert into books values (1,'Oracle','22-mar-05');
insert into books values (1,'Oracle','14-feb-07');
insert into books values (2,'Java','27-sep-03');
insert into books values (2,'Java','21-oct-05');
insert into books values (3,'Sap','12-dec-04');
insert into books values (3,'Sap','14-nov-05');
insert into books values (4,'Unix','19-apr-05');
insert into books values (4,'Unix','30-may-07');
end;
Expected output
1 Oracle 22-MAR-05
1 Oracle 14-FEB-07
4 Unix 19-APR-05
4 Unix 30-MAY-07
We have one more book of Oracle purchased in 2001, i don't what that in my output.
Only books purchased in both 2005 and 2007 should be in the output result.
Please help me how my query should be.
Thanks
Raghu

Answer 1

There are a variety of ways. Something like
SQL> ed
Wrote file afiedt.buf
  1  SELECT b.*
  2    FROM books b,
  3         (SELECT book_id
  4           FROM books
  5          WHERE extract( year from purchase_date ) = 2005
  6         INTERSECT
  7         SELECT book_id
  8           FROM books
  9          WHERE extract( year from purchase_date ) = 2007) purchases
10   WHERE b.book_id = purchases.book_id
11*    AND extract( year from b.purchase_date) IN (2005,2007)
SQL> /
   BOOK_ID NAME                 PURCHASE_
         1 Oracle               22-MAR-05
         1 Oracle               14-FEB-07
         4 Unix                 19-APR-05
         4 Unix                 30-MAY-07Justin