Adding Dates To Query

Question

What I am trying to achieve.
I have 3 tables.
tblCUSTDETAILS - Contains Customers Information.
tblFLTNUMS - Contains Faults The Customer Has
tblCONTACTS - Contains The Monthly Volume of Contacts by the Customer.
What I want to do is show the amount of contacts 3 months after the date of the fault. So I can say things like 3 month after a fault the customer still contacts us back as they have lost confidence with our service. etc.
The problem is that if the customer hasn't called back for a specific month then it doesn't record 0 and this is what I want.
WITH tblCUSTDETAILS AS (
    SELECT  '11111' AS CUST_ID, 'John Smith' AS CUST_NAME FROM DUAL UNION ALL
    SELECT  '11112' AS CUST_ID, 'Andy Wilson' AS CUST_NAME FROM DUAL
), tblFLTNUMS AS (
    SELECT  '11111' AS CUST_ID, TO_DATE('JAN-10', 'MON-YY') AS FLT_DT FROM DUAL UNION ALL
    SELECT  '11112', TO_DATE('FEB-10', 'MON-YY') FROM DUAL UNION ALL
    SELECT  '11112', TO_DATE('APR-10', 'MON-YY') FROM DUAL 
   tblCONTACTS AS (
    SELECT  '11111' AS CUST_ID, TO_DATE('JAN-10', 'MON-YY') AS CONTACT_DT, 5 AS CONTACT_VOL FROM DUAL UNION ALL
    SELECT  '11111', TO_DATE('FEB-10', 'MON-YY'), 3 FROM DUAL UNION ALL
    SELECT  '11112', TO_DATE('MAR-10', 'MON-YY'), 1 FROM DUAL UNION ALL
    SELECT  '11112', TO_DATE('MAY-10', 'MON-YY'), 2 FROM DUAL
SELECT  t1.cust_id,
        t2.cust_name,
        t1.flt_dt,
        t3.contact_dt,
        t3.contact_vol
FROM    tblFLTNUMS t1
JOIN    tblCUSTDETAILS t2
    ON t1.cust_id = t2.cust_id
JOIN    tblCONTACTS t3
    ON t1.cust_id = t3.cust_id
ORDER BY flt_dt, contact_dt, cust_name DESC
;   As you can see by the atttached example Joh Smith had a fault on the 01/01/2010 and contacted us on the 01/01, 01/02 and not on the 01/03 but I want the 01/03 to say 0.
As this is just a one of report I can not rebuild the tables so a SQL based solution is required.
I hope you can help.

Answer 1

I'm not sure what you are really after but I gave it a shot:
SQL> WITH tblCUSTDETAILS AS (
  2      SELECT  '11111' AS CUST_ID, 'John Smith' AS CUST_NAME FROM DUAL UNION ALL
  3      SELECT  '11112' AS CUST_ID, 'Andy Wilson' AS CUST_NAME FROM DUAL
  4  ), tblFLTNUMS AS (
  5      SELECT  '11111' AS CUST_ID, TO_DATE('JAN-10', 'MON-YY') AS FLT_DT FROM DUAL UNION ALL
  6      SELECT  '11112', TO_DATE('FEB-10', 'MON-YY') FROM DUAL UNION ALL
  7      SELECT  '11112', TO_DATE('APR-10', 'MON-YY') FROM DUAL
  8  ), tblCONTACTS AS (
  9      SELECT  '11111' AS CUST_ID, TO_DATE('JAN-10', 'MON-YY') AS CONTACT_DT, 5 AS CONTACT_VOL FROM DUAL UNION ALL
10      SELECT  '11111', TO_DATE('FEB-10', 'MON-YY'), 3 FROM DUAL UNION ALL
11      SELECT  '11112', TO_DATE('MAR-10', 'MON-YY'), 1 FROM DUAL UNION ALL
12      SELECT  '11112', TO_DATE('MAY-10', 'MON-YY'), 2 FROM DUAL
13  ), tblMonthParameters AS (
14          SELECT  MIN(FLT_DT) AS startMonth
15          ,       ADD_MONTHS(MAX(FLT_DT),2) AS endMonth
16          FROM    tblFLTNUMS
17  ), tblMONTHS AS (
18          SELECT  ADD_MONTHS(startMonth,ROWNUM - 1) AS DT
19          FROM    tblMonthParameters
20          CONNECT BY LEVEL <= MONTHS_BETWEEN(endMonth,startMonth) + 1
21  )
22  SELECT  t1.cust_id,
23          t2.cust_name,
24          t1.flt_dt,
25          t3.dt,
26          NVL(t3.contact_vol,0)   AS CONTACT_VOL
27  FROM    tblFLTNUMS t1
28  JOIN    tblCUSTDETAILS t2
29      ON t1.cust_id = t2.cust_id
30  JOIN    (
31                  SELECT  CUST_ID
32                  ,       CONTACT_VOL
33                  ,       DT
34                  FROM    tblCONTACTS PARTITION BY (tblCONTACTS.CUST_ID)
35                  RIGHT JOIN tblMONTHS  ON tblCONTACTS.CONTACT_DT = tblMONTHS.DT
36          ) t3
37      ON  t3.CUST_ID = T1.CUST_ID
38      AND MONTHS_BETWEEN(t3.DT,t1.FLT_DT) BETWEEN 0 AND 2
39  ORDER BY flt_dt, dt, cust_name DESC
40  ;
CUST_ CUST_NAME   FLT_DT              DT                           CONTACT_VOL
11111 John Smith  01/01/2010 00:00:00 01/01/2010 00:00:00                    5
11111 John Smith  01/01/2010 00:00:00 02/01/2010 00:00:00                    3
11111 John Smith  01/01/2010 00:00:00 03/01/2010 00:00:00                    0
11112 Andy Wilson 02/01/2010 00:00:00 02/01/2010 00:00:00                    0
11112 Andy Wilson 02/01/2010 00:00:00 03/01/2010 00:00:00                    1
11112 Andy Wilson 02/01/2010 00:00:00 04/01/2010 00:00:00                    0
11112 Andy Wilson 04/01/2010 00:00:00 04/01/2010 00:00:00                    0
11112 Andy Wilson 04/01/2010 00:00:00 05/01/2010 00:00:00                    2
11112 Andy Wilson 04/01/2010 00:00:00 06/01/2010 00:00:00                    0
9 rows selected.I added two more tables to your WITH clause. The tblMonthParameters calculates the minimum FLT_DT and maximum FLT_DT + 2 months based on your three month fault requirement. The tblMonths takes these input parameters and generates a dense month range.
This dense month range is then outer joined using the PARTITION BY syntax to the tblCONTACTS table to generate the range of months for each customer. This result is then used as a subquery to the original main query that you had joining based on the customer and FLT_DT. Where the customer did not contact for a particular month I've placed a 0 in the CONTACT_VOL column.
If this isn't correct please let me know. This solution depends on 10g so if you don't have it you may have to find another way to achieve this.
HTH!