let's say I have a KPI which is a simple calculation like
SUMX(FILTER(Table;Table[Date] < Today());Table[Column])
I would like to plot a time series of the KPI's past values (for example for the first day of every month since 01-01-2014), so for instance it is enough to create a new table - Trend_Table - with two columns - DATE, KPI and calculate each row's KPI value as
SUMX(FILTER(Table;Table[Date] < Trend_Table[Date]);Table[Column])
(it may not exactly work that way in DAX but you get the idea)
The problem is I really want to have online values, which means that once the September begins a new row with DATE = '01-09-2018' should be added automatically to the table 'Tren_Table'. Is it possible in Power BI? Any referalls greatly welcomed.