Aggregate sql select

Question

Hi,
I'm in Oracle 11g, need some help writing aggregate sql select. That might be really easy I hope.
We are doing some web analytics and counting clicks on a company’s web site, so I have to count sums on clicks, visitors and sessions from activity table.
t_agg_activity( date_key, site_id, segment_id, page_id, visitor_count, views_count, session_count)
The problem is with the Totals numbers. There are visitors and their segments. Segments are also divided by groups. So I need to count records and distinct visitors and distinct sessions.
Also I need three  records  for Totals: total all and total in group 1 and total in group 2 with the segment key -1, -2, -3 respectively. No Totals for group 3 needed.
Not sure how to deal with those totals. Should I use Roll Up function or analytic SUM function may be?
create table t_sites(site_id  NUMBER, site_code VARCHAR2(50));
insert into t_sites(site_id  , site_code )
values( 1, 'site_1');
insert into t_sites(site_id  , site_code )
values( 2, 'site_2');
insert into t_sites(site_id  , site_code )
values( 3, 'site_3');
create table t_segments(segment_id  NUMBER, segment_group VARCHAR2(50), segment_code VARCHAR2(50));
insert into t_segments(segment_id  , segment_group , segment_code )
values(1, 'seg_group_1', 'AAA');
insert into t_segments(segment_id  , segment_group , segment_code )
values(2, 'seg_group_1', 'BBB');
insert into t_segments(segment_id  , segment_group , segment_code )
values(3, 'seg_group_1', 'CCC');
insert into t_segments(segment_id  , segment_group , segment_code )
values(4, 'seg_group_2', 'DDD');
insert into t_segments(segment_id  , segment_group , segment_code )
values(5, 'seg_group_2', 'EEE');
insert into t_segments(segment_id  , segment_group , segment_code )
values(6, 'seg_group_2', 'FFF');
insert into t_segments(segment_id  , segment_group , segment_code )
values(7, 'seg_group_3', 'GGG');
insert into t_segments(segment_id  , segment_group , segment_code )
values(8, 'seg_group_3', 'HHH');
insert into t_segments(segment_id  , segment_group , segment_code )
values(9, 'seg_group_3', 'III');
insert into t_segments(segment_id  , segment_group , segment_code )
values(-1, 'Total All', 'Total');
insert into t_segments(segment_id  , segment_group , segment_code )
values(-2, 'Total seg_group_1', 'Total G1');
insert into t_segments(segment_id  , segment_group , segment_code )
values(-3, 'Total seg_group_2', 'Total G2');
create table t_activity( date_key NUMBER, page_id NUMBER, site_id  NUMBER, segment_id NUMBER, visitor_id NUMBER, session_id NUMBER);
insert into t_activity( date_key, page_id, site_id, segment_id, visitor_id, session_id)
values( 2456141, 1, 1, 1, 1, 1);
insert into t_activity( date_key, page_id,site_id, segment_id, visitor_id, session_id)
values( 2456141, 1, 1, 1, 1, 1);
insert into t_activity( date_key, page_id,site_id, segment_id, visitor_id, session_id)
values( 2456141, 1, 1, 1, 1, 2);
insert into t_activity( date_key, page_id,site_id, segment_id, visitor_id, session_id)
values( 2456141, 1, 1, 1, 2, 2);
insert into t_activity( date_key, page_id,site_id, segment_id, visitor_id, session_id)
values( 2456141, 1, 1, 1, 2, 2);
insert into t_activity( date_key, page_id,site_id, segment_id, visitor_id, session_id)
values( 2456141, 1, 1, 1, 2, 22);
insert into t_activity( date_key, page_id,site_id, segment_id, visitor_id, session_id)
values( 2456141, 1, 1, 4, 2, 10);
insert into t_activity( date_key, page_id,site_id, segment_id, visitor_id, session_id)
values( 2456141, 1, 1, 4, 2, 10);
insert into t_activity( date_key, page_id,site_id, segment_id, visitor_id, session_id)
values( 2456141, 1, 1, 4, 2, 10);
insert into t_activity( date_key, page_id,site_id, segment_id, visitor_id, session_id)
values( 2456141, 1, 1, 7, 3, 100);
insert into t_activity( date_key, page_id,site_id, segment_id, visitor_id, session_id)
values( 2456141, 1, 1, 7, 3, 100);
insert into t_activity( date_key, page_id,site_id, segment_id, visitor_id, session_id)
values( 2456141, 1, 1, 7,  3, 100);
create table t_agg_activity( date_key NUMBER, site_id NUMBER, segment_id NUMBER,  page_id NUMBER, visitor_count NUMBER, views_count NUMBER, session_count NUMBER)
Edited by: 955537 on Aug 28, 2012 11:19 AM

Answer 1

955537 wrote:
If you can help with the full query?
with t as (
           select  nvl2(segment_group,'Total ' || segment_group,'Total All') segment_group,
                   count(*) cnt
             from  t_activity a,
                   t_segments s
             where s.segment_id = a.segment_id
             group by rollup(segment_group)
select  segment_id,
         count(*)
  from   t_activity
  group by segment_id
union all
select  segment_id,
         cnt
   from  t,
         t_segments s
   where s.segment_group = t.segment_group
SEGMENT_ID   COUNT(*)
         1          6
         4          3
         7          3
        -1         12
        -2          6
        -3          3
6 rows selected.
SQL>  SY.