How to acomulate data from the actual table

[Juan_Camilo_Sie]

I have a table where I submit the information about the amount of “Things” that someone has count.

I want to have a column in which I can acomulate the information of counted things by someone.
I’m trying using SUM(Select:

sum(select([“Thing”],[“Someone”] = [“Someone”]))

But offcourse is not working due to SELECT has invalid inputs, but I don´t know how to do it

Thank you in advice