Sum of same fields in two different tables

Question

Hi ,
I am facing a problem, hope anyone would help
I have two tables.. here is the sample data..
create table t1
(item_ID NUMBER(2),
book_ID NUMBER(2),
price NUMBER(2))
insert into t1 (item_ID, book_ID, price) values (1,1,60);
insert into t1 (item_ID, book_ID, price) values (1,2,70);
insert into t1 (item_ID, book_ID, price) values (1,3,80);
insert into t1 (item_ID, book_ID, price) values (2,1,10);
insert into t1 (item_ID, book_ID, price) values (2,1,20);
insert into t1 (item_ID, book_ID, price) values (1,3,40);
create table t2
(item_ID NUMBER(2),
book_ID NUMBER(2),
price NUMBER(2))
insert into t2 (item_ID, book_ID, price) values (1,1,89);
insert into t2 (item_ID, book_ID, price) values (1,2,29);
insert into t2 (item_ID, book_ID, price) values (1,3,99);
insert into t2 (item_ID, book_ID, price) values (2,1,55);
insert into t2 (item_ID, book_ID, price) values (2,1,90);
insert into t2 (item_ID, book_ID, price) values (1,3,10);
as you can see, both tables have the same column names with different data. what
I require is that i need to calculate the SUM of price grouped by book_id from
both the tables in a single SQL statement output.
so my required output is this:
BOOK_ID SUM(PRICE)
1 323
2 99
3 229
where the SUM(price) for each book_id is for all the books in both the tables
where book_id = 1 and then 2 in the second row and then 3 in the third row.
Would anyone please help, as I am unable to write the query for this.?
Thanks,
Sonali.

Answer 1

<quote>I was just curious if we can do that by some other SQl query and using UNION ALL operator...</quote>
Of course there are other ways to do it ... but not necessarily better ... just to satisfy your curiosity:
flip@FLOP> select book_id,sum(price) from t1 group by book_id;
   BOOK_ID SUM(PRICE)
         1    5898240
         2    4587520
         3    7864320
         4    2621440
Elapsed: 00:00:01.02
flip@FLOP> select book_id,sum(price) from t2 group by book_id;
   BOOK_ID SUM(PRICE)
         1   30670848
         2    3801088
         3   15597568
         5    1310720
Elapsed: 00:00:02.06
flip@FLOP> SELECT book_id, sum(price)
  2  FROM ( select * from t1
  3         union all
  4         select * from t2
  5       )
  6  GROUP BY book_id;
 
   BOOK_ID SUM(PRICE)
         1   36569088
         2    8388608
         3   23461888
         4    2621440
         5    1310720
 
Elapsed: 00:00:04.01
flip@FLOP>
flip@FLOP> with a1 as
  2       (
  3         select book_id, sum(price) p
  4         from   t1
  5         group by book_id
  6       )
  7      ,a2 as
  8       (
  9         select book_id, sum(price) p
10         from   t2
11         group by book_id
12       )
13  select nvl(a1.book_id,a2.book_id), nvl(a1.p,0)+nvl(a2.p,0)  p
14  from  a1 full outer join a2 on (a1.book_id = a2.book_id)
15  ;
 
NVL(A1.BOOK_ID,A2.BOOK_ID)          P
                         1   36569088
                         2    8388608
                         3   23461888
                         4    2621440
                         5    1310720
 
Elapsed: 00:00:04.02