Sum rows with same values and write it in new cell

Question

I have the following table:

OrderNumber	Value
123	2
123	3
333	5
333	6
555	8
555	9

My goal is to sum all OrderNumbers with the same values (e.g. for OrderNumber 123 the sum should be 5) and output the result in a new row.

The output should be like this:

OrderNumber	Value	Result
123	2	5
123	3	5
333	5	11
333	6	11
555	8	17
555	9	17

I've seen some formulas beginning with =SUM(A2:A6;A2;B2:B6). Important to me is that the searching criteria must be dynamically because my table has about 1k rows.

Do you have any references or suggestions?

Answer 1

You need SUMIF() function.

=SUMIF($A$2:$A$7,A2,$B$2:$B$7)

If you are a Microsoft 365 user then can try BYROW() for one go.

=BYROW(A2:A7,LAMBDA(x,SUMIF(A2:A7,x,B2:B7)))