Can I use filter in SUMX?
SUMX calculates a sum over a table. The second part of the formula, FILTER(table, expression),tells SUMX which data to use. SUMX requires a table or an expression that results in a table. Here, instead of using all the data in a table, you use the FILTER function to specify which of the rows from the table are used.
Does filter order matter in DAX?
Rule #2: Filter order does NOT make a difference within a CALCULATE.