Help with formula how to select proper value

[#1]

Value   l_pdol1000 is culculated in chart table1 and = 42;

I need to get value from per_comm  field from different table2    where my value  l_pdol1000

will be between from_per  field and to_per  field     " from_per <=l_pdol1000  >=to_per"

{<from_per<= l_pdol1000,to_per<=l_pdol1000 >}per_comm   

Please Help with Formula.

Thank you