PL/SQL Split, separate a date into new dates according to black out dates!

Question

I have lets say a \"travel date\" and black out dates. I will split the travel date into pieces according to the black out dates.

Note: Travel Date can be between

Answer 1

This returns a discrete list of all dates that exist in the Travel Dates range but not in the Blackout Dates list, and then combines them using Oracle - Convert value from rows into ranges:

WITH traveldate AS
  (SELECT TO_DATE('2011 01 04','YYYY MM DD') AS start_date
         ,TO_DATE('2011 12 11','YYYY MM DD') AS end_date FROM DUAL)
    ,blackout AS
  (SELECT TO_DATE('2010 11 01','YYYY MM DD') AS start_date
         ,TO_DATE('2011 02 11','YYYY MM DD') AS end_date FROM DUAL
   UNION ALL
   SELECT TO_DATE('2011 01 20','YYYY MM DD') AS start_date
         ,TO_DATE('2011 02 15','YYYY MM DD') AS end_date FROM DUAL
   UNION ALL
   SELECT TO_DATE('2011 03 13','YYYY MM DD') AS start_date
         ,TO_DATE('2011 04 10','YYYY MM DD') AS end_date FROM DUAL
   UNION ALL
   SELECT TO_DATE('2011 03 20','YYYY MM DD') AS start_date
         ,TO_DATE('2011 06 29','YYYY MM DD') AS end_date FROM DUAL)
    ,days AS
  (SELECT TO_DATE('2010 01 01','YYYY MM DD') + ROWNUM d
   FROM DUAL CONNECT BY LEVEL <= 1000)
    ,base AS
  (SELECT d AS n
   FROM   days, traveldate
   WHERE  d >= traveldate.start_date AND d <= traveldate.end_date
   MINUS
   SELECT d AS n
   FROM   days, blackout
   WHERE  d >= blackout.start_date AND d <= blackout.end_date
  )
,lagged AS
(
    SELECT n, LAG(n) OVER (ORDER BY n) lag_n FROM base
)
, groups AS
(
    SELECT n, row_number() OVER (ORDER BY n) groupnum
      FROM lagged
      WHERE lag_n IS NULL OR lag_n < n-1
)
, grouped AS
(
    SELECT n, (SELECT MAX(groupnum) FROM groups
                 WHERE groups.n <= base.n
              ) groupnum
      FROM base
)
SELECT groupnum, MIN(n), MAX(n)
  FROM grouped
  GROUP BY groupnum
  ORDER BY groupnum;

Result:

GROUPNUM    MIN(N)          MAX(N)

1           16/02/2011  12/03/2011
2           30/06/2011  11/12/2011