Question

Is there an easy way to do this? By fully between, I mean don’t count the 7am or 7pm datetimes that are equal to the start or end time.

I imagine this can be done using the unix timestamp in seconds and a bit of algebra, but I can’t figure it out.

I’m happy to use something in PLSQL or plain SQL.

Examples:

start             end               num_7am_7pm_between_dates
2012-06-16 05:00  2012-06-16 08:00  1  
2012-06-16 16:00  2012-06-16 20:00  1
2012-06-16 05:00  2012-06-16 07:00  0
2012-06-16 07:00  2012-06-16 19:00  0
2012-06-16 08:00  2012-06-16 15:00  0
2012-06-16 05:00  2012-06-16 19:01  2
2012-06-16 05:00  2012-06-18 20:00  6 

Answer 1

I think this could be reduced further but I don’t have Oracle at my disposal to completely test this Oracle SQL:

SELECT StartDate
     , EndDate
     , CASE WHEN TRUNC(EndDate) - TRUNC(StartDate) < 1
             AND TO_CHAR(EndDate, 'HH24') > 19
             AND TO_CHAR(StartDate, 'HH24') < 7
            THEN 2
            WHEN TRUNC(EndDate) - TRUNC(StartDate) < 1
             AND (TO_CHAR(EndDate, 'HH24') > 19
              OR  TO_CHAR(StartDate, 'HH24') < 7)
            THEN 1
            WHEN TRUNC(EndDate) - TRUNC(StartDate) > 0
             AND TO_CHAR(EndDate, 'HH24') > 19
             AND TO_CHAR(StartDate, 'HH24') < 7
            THEN 2 + ((TRUNC(EndDate) - TRUNC(StartDate)) * 2)
            WHEN TRUNC(EndDate) - TRUNC(StartDate) > 0
             AND TO_CHAR(EndDate, 'HH24') > 19
              OR TO_CHAR(StartDate, 'HH24') < 7
            THEN 1 + ((TRUNC(EndDate) - TRUNC(StartDate)) * 2)
            ELSE 0
       END
FROM MyTable;

Thanks to @A.B.Cade for the Fiddle, it looks like my CASE Logic can be condensed further to:

SELECT SDate
     , EDate
     , CASE WHEN TO_CHAR(EDate, 'HH24') > 19
             AND TO_CHAR(SDate, 'HH24') < 7
            THEN 2 + ((TRUNC(EDate) - TRUNC(SDate)) * 2)
            WHEN TO_CHAR(EDate, 'HH24') > 19
              OR TO_CHAR(SDate, 'HH24') < 7
            THEN 1 + ((TRUNC(EDate) - TRUNC(SDate)) * 2)
            ELSE 0
       END AS MyCalc2
  FROM MyTable;