Kind of sum distinct

Question

Hi to everybody...i have to solve a big problem, and i can't find a way to get it..
i have a table like this
Italy 1000
Spain 2000
Germany 1500
and for some reason, i have to make a join, so the result is a duplicate rows...
Italy 1000 AA 50
Italy 1000 BB 50
Italy 1000 AA2 100
Italy 1000 CC 1500
Spain 2000 DD 100
Spain 2000 AA 30
Spain 2000 FF 50
Germany 1500 AA 100
Germany 1500 NN 200
in this table that i get, i have , WITH A SINGLE SELECT STATEMENT (beacuse i have to use business object)
Count the number of countries -> count( distinct country)
Sum the import that i had in the first table...so i have to get 1000+2000+1500
(it's like a sum of import for distinct countries).
How i can do this using a single select? I know the way to do it using 2 select, one inside the other, but i can't use it in business object.
Thank's in advance!
Edited by: user13012184 on 5-mag-2010 3.07

Answer 1

Hi,
user13012184 wrote:
Oracle Database 10g Enterprise Edition Release 10.2.0.4.0 - 64bi
create table PROVA1
COUNTRY VARCHAR2(50),
IMPORT NUMBER
insert into PROVA1 (COUNTRY, IMPORT)
values ('Italy', 1000);
insert into PROVA1 (COUNTRY, IMPORT)
values ('Spain', 2000);
insert into PROVA1 (COUNTRY, IMPORT)
values ('Germany', 1000);
commit;
select sum(import) from prova1 t
[4000]
create table PROVA2
COUNTRY VARCHAR2(50),
CITY VARCHAR2(50)
insert into PROVA2 (COUNTRY, CITY)
values ('Italy', 'Trieste');
insert into PROVA2 (COUNTRY, CITY)
values ('Italy', 'Venezia');
insert into PROVA2 (COUNTRY, CITY)
values ('Spain', 'Barcellona');
insert into PROVA2 (COUNTRY, CITY)
values ('Germany', 'Berlino');
insert into PROVA2 (COUNTRY, CITY)
values ('Germany', 'Colonia');
commit;
select sum(import) from prova1 t1 ,prova2 t2
where t1.country=t2.country
[6000]That's an excellent reply to Centinul's items 1. and 2.:
Centinul wrote:
It is always helpful to provide the following:
1. Oracle version (SELECT * FROM V$VERSION)
2. Sample data in the form of CREATE / INSERT statements.
3. Expected output
4. Explanation of expected output (A.K.A. "business logic")
5. Use \ tags for #2 and #3. See FAQ (Link on top right side) for details.Keep up the good work! Post items 3., 4. and 5. as well.
>
but i would like to have [4000], the sum of a import for every distinct country...Is that the answer to "3. Expected output"? If so, you already posted the answer yourself:
SELECT  SUM (import) AS sum_of_import
FROM     prova1          t
;Prova2 plays no role in this problem. That's fine: you won't use every table in every query.