Getting duplicates in Case and Count clause in Report Generation

Question

Hi all,
let me explain the Base first (just the Section which is in the scope of this code )then ill go to code and my problem.i have a Set of Pre-defined Tasks in *"TASK"* Table.i have a system which will provision the User Request by allotting the Particular Task to their Request.Each Request will mapped to the Instance of the (Pre-defined)Task, this will be maintained in a separate table *"TASK_INSTANCE"* against the user request id. Each task has a pre-defined duration.and their date of completion date will be stored in column of data type Time Stamp.
My scenario is i need to generate report based on the completion date.report requirement is , i need to give the count of tasks which having completion date as today,tomorrow and next day they grouped based on Task Names.
my problem is, im getting duplicates though i used the Distinct.There is no possible of duplicates by means of join, since im using group by task name.each Record in the Task_instance table has direct relation to the Task ID. For eg : im getting one row with the count satisfying the Condition and next row with empty set.i cant figure it out why happening.need your help in figuring out this.
Let me append the query below,
SELECT   task.task_name,
*(CASE*
WHEN ( (TRUNC (SYSDATE) - TRUNC (task_instance.ptd_pdd_date)) =
-1)
THEN
*(COUNT (task_instance.ptd_pdd_date))*
END)
AS "1_day_behind",
*(CASE*
WHEN ( (TRUNC (SYSDATE) - TRUNC (task_instance.ptd_pdd_date)) =
-2)
THEN
COUNT (task_instance.ptd_pdd_date)
END)
AS "2_day_behind",
*(CASE*
WHEN ( (TRUNC (SYSDATE) - TRUNC (task_instance.ptd_pdd_date)) =
-3)
THEN
COUNT (task_instance.ptd_pdd_date)
END)
AS "3_day_behind"
FROM   task, task_instance
WHERE       task.task_id = task_instance.task_id
AND task_instance.status_id = 1
AND task_instance.ptd_pdd_date IS NOT NULL
GROUP BY   (TRUNC (SYSDATE) - TRUNC (task_instance.ptd_pdd_date)),
task.task_name;
task_instance.status_id = 1 it refers to the task which are in "IN PROGRESS" state.
This is the (Sample) result set i am getting.In this, the task UI_Contact_Customer is repeated three times. with different count in separate rows and null in separate row .i need to avoid those duplicates.please advise.
TASK_NAME     | "1_DAY_BEHIND"     | "2_DAY_BEHIND"     | "3_DAY_BEHIND" |
______________________________|________________|_________________|_________________|               
UI_Conduct_Fiber_Plant_Survey_____|________________|________________ |_________________|
UI_Conduct_Site_Survey__________ |_______________ |________________ |_________________|
UI_ConductFiberSurvey_C___________|________________|________________ |________________|
UI_ConductSiteSurvey_C __________|________________|_________________|_________________|
UI_Contact_Customer_____________|________________|_________________|_________________|
UI_Contact_Customer ____________ |_______10_______|________________ |_________________|
UI_Contact_Customer_____________|________________|_______ 12_______|_________________|
UI_Create_Account_Equip_C_______ |________________|_________________|_________________|
UI_Create_Account_Equipment_____ |________________|_________________|_________________|
UI_Create_CM_Ticket           |     | | |
______________________________|________________|_________________|_________________|
In the Above result set, especially UI_Contact_Customer task,ten of their instance having completion date tomorrow and 12 instance having next day as completion date. i need get all those as single row without any duplicates.
Thanks,
Jeevanand.K

Answer 1

hey super dude,
it really works fine.matching my requirement exactly.
My hearty appreciation to you friend, and a small appreciation for me tooo,because i formed the base query. :-)
i used the below query,it requirement gets completed.
A big Thanks for your super fast Response
SELECT   task.task_name,
COUNT(CASE
WHEN TRUNC (SYSDATE) - TRUNC (task_instance.ptd_pdd_date) BETWEEN 1
AND  14
THEN
*1*
END)
AS "TWO weeks older",
COUNT(CASE
WHEN TRUNC (SYSDATE) - TRUNC(task_instance.ptd_pdd_date) =
-1
THEN
*1*
END)
AS "1_day_left",
COUNT(CASE
WHEN ( (TRUNC (SYSDATE)
- TRUNC (task_instance.ptd_pdd_date)) = -2)
THEN
*1*
END)
AS "2_day_left",
COUNT(CASE
WHEN ( (TRUNC (SYSDATE)
- TRUNC (task_instance.ptd_pdd_date)) = -3)
THEN
*1*
END)
AS "3_day_left",
COUNT(CASE
WHEN ( (TRUNC (SYSDATE)
- TRUNC (task_instance.ptd_pdd_date)) = -4)
THEN
*1*
END)
AS "4_day_left",
COUNT(CASE
WHEN ( (TRUNC (SYSDATE)
- TRUNC (task_instance.ptd_pdd_date)) = -5)
THEN
*1*
END)
AS "5_day_left",
COUNT(CASE
WHEN ( (TRUNC (SYSDATE)
- TRUNC (task_instance.ptd_pdd_date)) = -6)
THEN
*1*
END)
AS "6_day_left",
COUNT(CASE
WHEN ( (TRUNC (SYSDATE)
- TRUNC (task_instance.ptd_pdd_date)) >= -7)
THEN
*1*
END)
AS "After one week"
FROM   task, task_instance
WHERE   task.task_id = task_instance.task_id AND task_instance.status_id = 1
GROUP BY   task.task_name;
Thanks,
Jeevanand.K