Vacation period

Question

Hi all,
I have two tables,
CREATE TABLE HOLIDAYS
  START_DATE  DATE,
  END_DATE    DATE
Insert into HOLIDAYS
   (START_DATE, END_DATE)
Values
   (TO_DATE('05/01/2001', 'DD/MM/YYYY'), TO_DATE('10/01/2001', 'DD/MM/YYYY'));
Insert into HOLIDAYS
   (START_DATE, END_DATE)
Values
   (TO_DATE('01/02/2001', 'DD/MM/YYYY'), TO_DATE('03/02/2001', 'DD/MM/YYYY'));   
Insert into HOLIDAYS
   (START_DATE, END_DATE)
Values
   (TO_DATE('02/10/2002', 'DD/MM/YYYY'), TO_DATE('25/10/2002', 'DD/MM/YYYY'));   
COMMIT;
CREATE TABLE EMP_VAC
  EMP_ID      NUMBER(5),
  START_DATE  DATE,
  VAC_LENGTH  NUMBER(3),
  END_DATE    DATE
Insert into EMP_VAC
   (EMP_ID, START_DATE, VAC_LENGTH)
Values
   (10, TO_DATE('01/01/2001', 'DD/MM/YYYY'), 6);
Insert into EMP_VAC
   (EMP_ID, START_DATE, VAC_LENGTH)
Values
   (20, TO_DATE('01/01/2001', 'DD/MM/YYYY'), 28);   
Insert into EMP_VAC
   (EMP_ID, START_DATE, VAC_LENGTH)
Values
   (10, TO_DATE('01/01/2001', 'DD/MM/YYYY'), 2);    
Insert into EMP_VAC
   (EMP_ID, START_DATE, VAC_LENGTH)
Values
   (40, TO_DATE('01/01/2003', 'DD/MM/YYYY'), 1);  
COMMIT;
select * from HOLIDAYS;
START_DATE END_DATE
05/01/2001 10/01/2001
01/02/2001 03/02/2001
02/10/2002 25/10/2002
select * from EMP_VAC;
    EMP_ID START_DATE VAC_LENGTH END_DATE
        10 01/01/2001          6
        20 01/01/2001         28
        10 01/01/2001          2
        40 01/01/2003          1
I want END_DATE for every a vacation,
and i want check overlap with holidays period,
ex: Employee 10 make this vacation
    EMP_ID START_DATE VAC_LENGTH END_DATE
        10 01/01/2001          6
and overlap with holidays
START_DATE END_DATE
05/01/2001 10/01/2001    
START_DATE for a vacation  01/01/2001 for 6 days :
I have overlap with  
01/01/2001 6 days and END_DATE 06/01/2001  
this period overlap with holidays
I will Except period holidays(05/01/2001 , 10/01/2001)
to become End_date 12/01/2001
Output Desired
    EMP_ID START_DATE VAC_LENGTH END_DATE
        10 01/01/2001          6 12/01/2001
        20 01/01/2001         28 07/02/2001
        10 01/01/2001          2 26/10/2002
        40 01/01/2003          1 01/01/2003
Thanks in advance
BANNER
Oracle Database 10g Enterprise Edition Release 10.2.0.4.0 - Prod
PL/SQL Release 10.2.0.4.0 - Production
CORE    10.2.0.4.0 ;     Production
TNS for Solaris: Version 10.2.0.4.0 - Production
NLSRTL Version 10.2.0.4.0 - Production Edited by: 900510 on Jul 25, 2012 5:29 AM

Answer 1

Hi,
I think you want something like this:
WITH     non_holidays     AS
     SELECT     TO_DATE ('1', 'J')     AS start_date
     ,     MIN (start_date) - 1     AS end_date
     FROM     holidays
    UNION ALL
         SELECT     end_date + 1                    AS start_date
     ,     LEAD ( start_date
               , 1
               , DATE '9999-12-30'
               ) OVER (ORDER BY  start_date) - 1     AS end_date
     FROM    holidays
,     all_overlap     AS
     SELECT     e.emp_id, e.start_date, e.vac_length
     ,     GREATEST (e.start_date, n.start_date)     AS f_start_date
     ,     n.end_date                    AS f_end_date
     FROM     emp_vac          e
     JOIN     non_holidays     n  ON   n.end_date     >= e.start_date
--     WHERE     ...          -- if you need any filtering, put it here
,     got_total_length     AS
     SELECT     a.*
     ,     SUM (f_end_date + 1 - f_start_date)
              OVER ( PARTITION BY  emp_id, start_date
                      ORDER BY        f_start_date
                )       AS total_length
     FROM    all_overlap  a
SELECT       emp_id, start_date, vac_length
,       MIN (f_end_date + (vac_length - total_length))     AS end_date
FROM       got_total_length
WHERE       total_length     >= vac_length
GROUP BY  start_date, emp_id, vac_length
ORDER BY  start_date, emp_id
;Thanks for posting the CREATE TABLE and INSERT statements, and the desired results. Remember why you need to do that: so that the people who want to help you can re-create the problem and test their ideas. If you post statements that don't work, or the wrong results, then it's not all that helpful. Please test your code (and correct it, if necessary) before posting. All of the INSERT statements you posted for emp_vac have errors. I suspect that the two rows for emp_id=10 should have different start_dates, and that either the data or results for emp_id=20 have some mistake.
This assumes that holiday periods don't overlap, and that the same employee can't have overlapping vacations.
This does not produce the results you posted, given your sample data.
If if does not produce the resutls you really want, then point out where it is wrong, and explain how you get the right results in those places.
You can simplify this a little if you add an impossibly early row to the holidays table. For example, if this application tracks vacation time in a company that was founded in 1998, then consider adding a row like this to the holidays table:
Insert into HOLIDAYS
   (START_DATE,                            END_DATE)
Values
   (TO_DATE ('01/01/1900', 'DD/MM/YYYY'),  TO_DATE ('31/12/1997', 'DD/MM/YYYY')); Then you won't need the first branch of the UNION in sub-query non_holidays.