Unable to retrive the data using self join

Question

I am trying to find the time taken to close a ticket. The ticket goes through various stages: NEW, INPROCESS, CLOSED, REOPENED. If the ticket is reopened then the next stage would be INPROCESS and then CLOSED.
The CC_TICKET_INFO table contains information about the last stage of the ticket. CC_TICKET_HISTORY table contains information about all the stages of the ticket.
The challenge here is if the ticket is reopened then it should be counted as 2 instances instead of 1.
First instance from stages: NEW --> INPROCESS --> CLOSE
Second instance from stages: REOPEND --> INPROCESS --> CLOSE.
Follwoing SQL is to generate the data:
CREATE TABLE CC_TICKET_INFO
  TICKET_ID VARCHAR2(20 BYTE) NOT NULL
, TICKET_STATUS VARCHAR2(60 BYTE)
, created_date timestamp(6)
, LAST_CHANGED timestamp(6)
, ASSIGNED_TO VARCHAR2(20)
, CONSTRAINT PK_CC_TICKET_INFO PRIMARY KEY
    ticket_id
CREATE TABLE CC_TICKET_HISTORY
  TICKET_ID VARCHAR2(20 BYTE) NOT NULL
, TICKET_STATUS VARCHAR2(60 BYTE)
, CREATED_DATE TIMESTAMP(6) NOT NULL
, ASSIGNED_TO VARCHAR2(255 BYTE)
, CREATED_BY VARCHAR2(60 BYTE)
, CONSTRAINT PK_CC_TICKET_HISTORY PRIMARY KEY
    TICKET_ID
  , CREATED_DATE
insert into cc_ticket_history values ('D21207155', 'NEW', '6/28/2013 17:28:59', null, 'jsg-st');
insert into cc_ticket_history values ('D21207155', 'INPROCESS', '6/28/2013 17:48:19', 'ah-eg', 'ah-eg');
insert into cc_ticket_history values ('D21207155', 'CLOSED', '6/28/2013 18:54:23', 'ah-eg', 'ah-eg');
insert into cc_ticket_history values ('D21207155', 'REOPENED', '7/2/2013 19:55:04', 'ah-eg', 'jsg-st');
insert into cc_ticket_history values ('D21207155', 'INPROCESS', '7/2/2013 20:11:17', 'sr-eg', 'sr-eg');
insert into cc_ticket_history values ('D21207155', 'CLOSED', '7/2/2013 23:06:16', 'sr-eg', 'sr-eg');
insert into CC_TICKET_INFO values ('D21207155', 'CLOSED', '6/28/2013 17:28:59', '7/2/2013 23:06:16', 'sr-eg');
I want to find the time difference betwen '6/28/2013 18:54:23' and '6/28/2013 17:28:59' (First instance)
and between '7/2/2013 23:06:16' and '7/2/2013 19:55:04' (Second instance)
The closest I am getting is the through this query:
select L.ticket_id, L.CREATED_DATE, R.CREATED_DATE as close_date, L.TICKET_STATUS, R.TICKET_STATUS from cc_ticket_history L RIGHT join cc_ticket_history R on (L.rowid < R.rowid) where (L.TICKET_STATUS = 'NEW' AND R.TICKET_STATUS ='CLOSED') OR (L.TICKET_STATUS = 'REOPENED' AND R.TICKET_STATUS ='CLOSED');
Can it be done through SQL?

Answer 1

select ticket_id,ticket_status,created_date,
       case when ticket_status = 'CLOSED'
             and lead(ticket_status) over (partition by ticket_id order by created_date) = 'REOPENED'
            then lead(created_date) over (partition by ticket_id order by created_date) - created_date
            when ticket_status = 'REOPENED'
             and lag(ticket_status) over (partition by ticket_id order by created_date) = 'CLOSED'
            then created_date - lag(created_date) over (partition by ticket_id order by created_date)
       end time_difference
  from cc_ticket_history
where ticket_status in ('CLOSED','REOPENED')
TICKET_ID
TICKET_STATUS
CREATED_DATE
TIME_DIFFERENCE
D21207155
CLOSED
28-JUN-13 06.54.23.000000 PM
+000000004 01:00:41.000000
D21207155
REOPENED
02-JUL-13 07.55.04.000000 PM
+000000004 01:00:41.000000
D21207155
CLOSED
02-JUL-13 11.06.16.000000 PM
Regards
Etbin