DAX SUM per group

1. What is the difference between sum () and SUMX ()?
2. What is SUMX?
3. Can we do GroupBy in DAX?

What is the difference between sum () and SUMX ()?

SUMX is an iterator function and takes a different approach. Unlike SUM, SUMX is capable of performing row-by-row calculations and iterates through every row of a specified table to complete the calculation. SUMX then adds all the row-wise results of the iterations of the given expression.

What is SUMX?

SUMX is an Iterator Function

Iterator functions perform a row-by-row iteration and complete an evaluation. SUMX iterates through each row of the table and then aggregates the values after applying all context filters, then applies an additional piece of logic before producing the final summation.

Can we do GroupBy in DAX?

GROUPBY is primarily used to perform aggregations over intermediate results from DAX table expressions. For efficient aggregations over physical tables in the model, consider using SUMMARIZECOLUMNS or SUMMARIZE function.