Amount up to the lower limit of the selected date

[qurbanolum]

How to choose the amount up to the lower limit? That is, I chose the lower time limit, for example, the first of April 2020. I need to print the sum of all dates that are below this lower bound i.e {beginning of the year} to {lower time limit}. I tried doing this 

Sum({<SOURCE={'FMBDP_SUM_PERC_B'}, Date={'<=$(=Date(min(Date)))'}>} SUM)

but it didnt work.