Creating new collum that calculates average

Hello

I would like to create seperated table where would be name so i can connect it to others and my own collums.

i need 3 of them (min, max, average) i alredy was able to find some function and tried it: ( every function basicly returns only one number for every row same i don't need average pre row but per collum)

Problem here is basicly this function does that if i have 5 unique rows then it will return 25 rows connecting exit from every row to every row (5 unique row -> function -> 25 rows and from that only 5 unique)