How to get previous deposit amount. This set analysis is not helping me. Trying this from so long

[rajnirughwani]

Please help me with this calculation. 

Thanks a lot in advance

Here I have 3 tables.

I want to calculate ratio based on table 1/2

I want values of Feb-21 of table 1/Jan-21 of table 2 (This is basically getting values of current month from table 1 / previous month value from table 2)

But somehow I can't get the values of previous month so the ratio calculation is incorrect.

Can someone pls help me with Set analysis statement

I am using this for DC count/DP count

if(Card = 'VP', Count(if(stateInt ='0' and txType ='MChargebck' and [chargebckdate.autoCalendar.Month], ChargebckID))
/
Count({<stateInt={'0'},txType={'CDeposit'},created_month = ${"=addmonths([created.autoCalendar.YearMonth], -1)"}>}originTxId),

if(Card = 'Mcard', Count(if(stateInt ='0' and txType ='MChargebck' and [chargebckdate.autoCalendar.Month], ChargebckID))
/
Count({<stateInt={'0'},txType={'CDeposit'},created_month = ${"=addmonths([created.autoCalendar.YearMonth], -1)"}>}originTxId)))