Request help with query group by

Question

Hi,
I have the following table structure with values
CREATE TABLE DUMMY
    SR_NUMBER          VARCHAR2(100 CHAR),
    ASSIGNMENT_GROUP   VARCHAR2(100 CHAR),
    REASSIGNMENT_COUNT VARCHAR2(100 CHAR),
    CREATED DATE,
    CLOSED DATE,
    TARGET_DATE DATE
insert into dummy values('AAA','A','1','02-OCT-11','25-OCT-11','09-OCT-11');
insert into dummy values('ABC','A','1','03-SEP-12','26-SEP-11','10-SEP-11');
insert into dummy values('AVB','A','1','02-NOV-13','25-NOV-13','09-NOV-13');
insert into dummy values('AFT','B','1','02-OCT-11','25-OCT-11','09-OCT-11');
insert into dummy values('ACS','B','1','02-JAN-12','25-JAN-12','09-JAN-12');
insert into dummy values('AVC','B','1','02-OCT-13','25-OCT-13','09-OCT-13');
insert into dummy values('AAD','B','1','02-MAR-14','25-MAR-14','09-MAR-14');
insert into dummy values('AAA','C','1','02-OCT-11','25-OCT-11','09-OCT-11');
insert into dummy values('AAA','D','1','02-JUN-11','25-JUN-11','09-JUN-11');
insert into dummy values('AAA','E','1','02-APR-12','25-APR-12','09-APR-12');
insert into dummy values('AAA','A','1','02-FEB-13','25-FEB-13','09-FEB-13');
?I have the following requirement, the output should be:
Ticket count (sr_number)
% of tickets inside DL
Number of tickets inside DL
Average cycle time (cycle time = closed date - created date)
Total cycle time (cycle time = closed date - created date)
Number of reassignments (sum)
DL - (deadline) formula is, closed date <= target_date
This should be displayed, grouped by year, then month and then by assignment group. The values should be in descending order(dates) Not sure how group by will work here.
I am able to write the basic code for the above, but group by based on year, month and assignment group is pretty confusing to me.
Can someone provide me a good code...

Answer 1

This may not give you exactly what you want, but hopefully, it will give you something to work with:
WITH tickets AS (
  SELECT TO_CHAR(created, 'YYYY') created_year,
         TO_CHAR(created, 'MM') created_month,
         assignment_group,
         COUNT(sr_number) ticket_count,
         AVG(closed - created) avg_cycle_time,
         SUM(closed - created) tot_cycle_time,
         COUNT(reassignment_count) reassign_count
   FROM dummy
   GROUP BY TO_CHAR(created, 'YYYY'),
            TO_CHAR(created, 'MM'),
            assignment_group
dl_tickets AS (
  SELECT TO_CHAR(created, 'YYYY') created_year,
         TO_CHAR(created, 'MM') created_month,
         assignment_group,
         COUNT(sr_number) ticket_in_dl_count
    FROM dummy
    WHERE closed <= target_date
    GROUP BY TO_CHAR(created, 'YYYY'),
          TO_CHAR(created, 'MM'),
          assignment_group
SELECT t.created_year,
       t.created_month,
       t.assignment_group,
       t.ticket_count,
       NVL(dl.ticket_in_dl_count, 0) ticket_in_dl_count,
       NVL(dl.ticket_in_dl_count/t.ticket_count, 0) * 100 pct_ticket_in_dl_count,
       t.avg_cycle_time,
       t.tot_cycle_time,
       t.reassign_count
  FROM tickets t,
       dl_tickets dl
  WHERE t.created_year = dl.created_year (+)
  AND t.created_month = dl.created_month (+)
  ORDER BY created_year DESC, created_month DESCEdited by: user1983440 on May 27, 2013 3:47 PM - Added reassign_count
Edited by: user1983440 on May 27, 2013 3:54 PM - Added ORDER BY