Recursive Sum in Excel

Question

Hello,

In the above example, how would I create a recursive or recursive workaround formula so that I can get the sum for the account number with multiple iterations of the account number dispersed throughout the leftmost account number column?

This is a toy example but if there were 100 unique account numbers in the right account number column with multiple iterations so ~10,000 entries in the left most account number column.

I want to do this as a formula because the data shape/size can and will change so a pivot table would not work as that needs to refreshed each time the shape changes.

I have an inkling the aggregate() function will come into play but I can't put my finger exactly on how to do it.

Does anyone have any thoughts? Thanks

Answer 1

=SUMIF() was born for this moment

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