How to create a date drop box that displays yyyy-mm till three months ago

[Galaxy98]

The current date dropdown is developed using a multibox that displays year month(yyyymm) till current month.

Now the current requirement of the client is to make changes in the expression, such that it displays date till 3 months ago as there is a 3 month delay in the data load.

current application : 

It is displaying date till last month like below, but now it should display from 202112( 3months ago)

[pooja_prabhu_n]

Hi,

Create last 3 month date column in script and use that in the multibox

if (monthstart(ReoportPeriod) > monthstart(addmonths(Today(),-3)), Date(MonthStart(ReoportPeriod),'YYYYMM')) as last3months,