Join to Calendar Table - 5 Business Days

Question

So this is somewhat of a common question on here but I haven\'t found an answer that really suits my specific needs. I have 2 tables. One has a list of ProjectClosedDates. The o

Answer 1

Completely untested and not thought through:

If the concept of "business days" is common and important in your system, you could add a column "Business Day Sequence" to your table. The column would be a simple unique sequence, incremented by one for every business day and null for every day not counting as a business day.

The data would look something like this:

Date       BDAY_SEQ
========== ========
2014-03-03    1
2014-03-04    2
2014-03-05    3
2014-03-06    4
2014-03-07    5
2014-03-08    
2014-03-09    
2014-03-10    6

Now it's a simple task to find the N:th business day from any date. You simply do a self join with the calendar table, adding the offset in the join condition.

select a.actual_date
      ,b.actual_date as nth_bussines_day
  from DateTable a
  join DateTable b on(
       b.bday_seq = a.bday_seq + 5
  );