Question

I need to sum values that are + 2 months or within a quarter period (related date table)

is there a way to use dense rank to partition those periods (custom periods)?

select
FiscalMonth
,Value
from table

Answer 1

The sql will have to do the following:

1. Join the value table and the period table
2. Include the period in the select list and sum the value, grouping by the period

i.e

 select b.period, sum(a.value)
  from table a 
    inner join period b on a.FiscalMonth between b.StartMonth and b.EndMonth
     group by b.period

Note: The join condition will have to be modified based on what data you actually have in the period table.

Hope this helps