Function to return Job History from the Employee Assignment Form (EBS)

Question

Hi All,
I was hoping to get some help from some SQL and PL/SQL experts on a problem which I’ve been battling to solve, without lots of subquery and self joins and performance problems.
I would ideally like to create a PL/SQL function that would return an Assignment Effective Start Date from an employees record in HR eBusiness Suite based on a few conditions.
I find it easiest to explain with the below table example, which is for a single person, lets say person_id = 3546:
*<PRE> ID Effective Start Date Effective End Date </PRE>*
<PRE> 01 01-DEC-2009 31-DEC-2009 </PRE>
<PRE> 01 *01-NOV-2009* 30-NOV-2009 </PRE>
<PRE> 88 01-OCT-2009 31-OCT-2009 </PRE>
<PRE> 01 01-SEP-2009 30-SEP-2009 </PRE>
<PRE> 67 01-AUG-2009 31-AUG-2009 </PRE>
Above are all the assignments for person_id 3546 with the ID of the Job/Grade they have been assigned. What I need to achieve is, that if I run a report as of the 15-DEC-2009, I would like see the 'Effective Start Date' of '01-NOV-2009' for the most recent ID that has been assigned to the person, in this case ID 01. It shouldn't group ID 01 and give the the date of '01-SEP-2009'.
Some more examples:
If I change the as of date to '10-NOV-2009' and run the report, i would get an 'Effective Start Date' of '01-NOV-2009' for ID 01.
If I change the as of date to '15-OCT-2009' and run the report, i would get an 'Effective Start Date' of '01-OCT-2009' for ID 88.
If I change the as of date to '29-SEP-2009' and run the report, i would get an 'Effective Start Date' of '01-SEP-2009' for ID 01 .
Have i explained enough?? And has anyone some ideas?
Many thanks,
Lance

Answer 1

The logic behind this, is that for an employee I need to determine how long that employee has been in there current job for. In the example I gave, the ID relates to the job ID and walking through the assignments this is what happens.
At '01-AUG-2009' the employee was at job id 67.
At '01-SEP-2009' the employee changed jobs and therefore their new ID was 01.
At '01-OCT-2009' the employee was temporarily promoted to job D of 88.
However at '01-NOV-2009' they returned to the previous grade ID of 01.
Therefore if I ask the question, as of today’s date, how long has the person been in their current job for. I would need to calculate the days from today - '01-NOV-2009'. I wouldn't take '01-DEC-2009' into consideration, because the employee was in the same job the previous month/assignment as well, therefore I need to take the min of these two dates to show the date of when the person first had a job ID of 01.
With regards to the logic shown below, this is similar to the date track function found across HR eBusiness forms. Depending on that 'As of Date' is entered, should return the date when that person was first in their current job.
as of 15-DEC-2009 should give 01-NOV-2009
as of 10-NOV-2009 should give 01-NOV-2009
as of 29-SEP-2009 should give 01-SEP-2009
Within the long winded SQL I have written, it contains the following condition: 'As of Date' >= 'Effective Start Date'. This is acting as my date track feature to only show assignments available to the employee at a particular date. The below code is taken from Oracle’s view called hrfg_job_history. I have had to use this to get my data, but at a cost of performance.
SELECT /* unique attributes */ bgrt.NAME business_group_name,
        peo.full_name person_name, job.NAME job_name,
        ass.effective_start_date effective_start_date,
        hr_discoverer.check_end_date
                                   (asf.effective_end_date)
                                                           effective_end_date /* foreign key resolutions */,
        peo.employee_number employee_number,
        ass.assignment_number assignment_number /* ids */,
        ass.assignment_id assignment_id,
        ass.business_group_id + 0 business_group_id, ass.job_id job_id,
        ass.person_id person_id
  FROM hr_all_organization_units bgr,
       hr_all_organization_units_tl bgrt,
       per_jobs job,
       per_people_x peo,
       per_assignments_f asf,
       per_assignments_f ass
WHERE ass.job_id = job.job_id
   AND ass.person_id = peo.person_id
   AND ass.business_group_id + 0 = bgr.organization_id
   AND bgr.organization_id = bgrt.organization_id
   AND bgrt.LANGUAGE = USERENV ('LANG')
   AND ass.assignment_type = 'E'
   AND NOT EXISTS (
          SELECT NULL
            FROM per_assignments_f ass1
           WHERE ass1.assignment_id = ass.assignment_id
             AND NVL (ass1.job_id, 9.9) + 0 = NVL (ass.job_id, 9.9) + 0
             AND ass1.effective_start_date =
                    (SELECT MAX (ass2.effective_start_date)
                       FROM per_assignments_f ass2
                      WHERE ass2.assignment_id = ass1.assignment_id
                        AND ass2.effective_start_date <
                                                      ass.effective_start_date)
             AND ass1.assignment_type = 'E')
   AND ass.assignment_id = asf.assignment_id
   AND asf.effective_end_date =
          (SELECT MAX (assf.effective_end_date)
             FROM per_assignments_f ass3, per_assignments_f assf
            WHERE ass3.assignment_id = ass.assignment_id
              AND ass3.assignment_id = assf.assignment_id
              AND NVL (ass3.job_id, 9.9) + 0 = NVL (ass.job_id, 9.9) + 0
              AND assf.assignment_type = 'E'
              AND ass3.assignment_type = 'E' /* check for end of time dates */
              AND (   (    assf.effective_start_date =
                                                      ass.effective_start_date
                       AND ass.effective_end_date =
                                          TO_DATE ('31-12-4712', 'DD-MM-YYYY')
                       AND assf.effective_end_date = ass.effective_end_date
                      ) /* check for rows which have changes after */
                   OR (    ass3.effective_start_date >=
                                                      ass.effective_start_date
                       AND (assf.effective_end_date =
                               (SELECT MIN (ass4.effective_start_date) - 1
                                  FROM per_assignments_f ass4
                                 WHERE ass4.assignment_id = ass.assignment_id
                                   AND ass4.effective_start_date >=
                                                     ass3.effective_start_date
                                   AND ass4.assignment_type = 'E'
                                   AND (NVL (ass4.job_id, 9.9) + 0 <>
                                                      NVL (ass.job_id, 9.9)
                                                      + 0
                      ) /* check for rows which do not have changes after */
                   OR (    ass3.effective_start_date =
                                                      ass.effective_start_date
                       AND NOT EXISTS (
                              SELECT NULL
                                FROM per_assignments_f ass7
                               WHERE ass7.assignment_id = ass.assignment_id
                                 AND ass7.effective_start_date >
                                                     ass3.effective_start_date
                                 AND ass7.assignment_type = 'E'
                                 AND (NVL (ass7.job_id, 9.9) + 0 <>
                                                      NVL (ass.job_id, 9.9)
                                                      + 0
                       AND (assf.effective_end_date =
                                          TO_DATE ('31-12-4712', 'DD-MM-YYYY')
   AND ass.business_group_id + 0 =
                 NVL (hr_general.get_business_group_id, ass.business_group_id)Any more ideas?
thanks,
Lance