Calculation with an dynamic additional parameter

[Anonymous]

Dear experts,

I need an expert work for my requirement. I have two tables which are consisting from main data table and table with only have dates of last day of months. I want to bring dates to table and calculate an additional field named as 'Deferred amount'by below formula

Formula =((Expiry Date-Calculation Date)/(Expiry Date-Starting Date))*Amount

But I am having an other concern since table1 is having more than 500K records and calculation of each record with each date again and again can be also challenging.

So I need to calculate this values with most efficient way.

Thanks in advance and any help will be appreciated.

Table 1

Table1
Starting Date	Expiry Date	Amount
6/1/2016	6/1/2017	100
3/1/2016	3/1/2017	250
5/15/2016	5/5/2018	300
1/1/2015	6/1/2017	400

Date_Table

1/31/2016

2/29/2016

3/31/2016

4/30/2016

5/31/2016

6/30/2016