What is the principle of sumproduct function in Excel? - excel

Question

This function can also calculate something like the result of sumifs if I put an array into the criteria argument: =sumproduct(sumifs(sumrange, criteria range, criteria)). It gives me the sum of the sum of all the criterion in the array. If I just do =sumifs(sumrange,criteria range, criteria) and the criterion is an array, then the result would be zero. I could only check the result by pressing F9 and it gives me the sum of each criteria separately. Why can sumproduct function add up all the separate values here?

Answer 1

When you use this formula
=SUMIFS(sumrange,criteria range, criteria)
with a range in place of the criteria then the result is an array of values
To get the result you want you can enclose that in SUM function......but then the formula needs to be "array entered" with CTRL+SHIFT+ENTER.....so using SUMPRODUCT is a way to avoid array entry. Because the result of SUMIFS is a single array SUMPRODUCT has nothing to multiply so it just sums the array
In short, when fed a single array SUMPRODUCT just sums the contents, e.g.
=SUMPRODUCT({1,2,3}) = 6

Answer 2

SumProduct is a very particular formula and you'll see it used in many occasions as a workaround to using array formulas, but only when it's used as a substitute of a point-array formulas (array formulas entered into a single cell), because it works with arrays by default.
In your particular case, you seem to get 0 with SUM(SUMIFS) as pure coincidence, because the sum of elements that are true for the first element of your array criterion is 0.
If you have, for example, a table as such:
A B C
1 t t
2 f f
3 t
4 x
5 x
and use the formula:
=SUM(SUMIFS($A$1:$A$5,$B$1:$B$5,$C$1:$C$2))
You will get 4 as a result, because it will only evaluate the first element of your condition array. If you instead enter it as an array formula with Ctrl + Shift + Enter, it will evaluate the condition with all the elements of your conditional array, working as such:
Evaluate =SUMIFS({1,2,3,4,5},{t,f,t,x,x},{t})
Return =SUM({1,2,3,4,5}*{1,0,1,0,0}) => SUM({1,0,3,0,0}) => 4
Store 4 in the first position of the temporary array {4,NULL}
Evaluate =SUMIFS({1,2,3,4,5},{t,f,t,x,x},{f})
Return =SUM({1,2,3,4,5}*{0,1,0,0,0}) => SUM({0,2,0,0,0}) => 2
Store 2 in the second position of the temporary array {4,2}
Evaluate =SUM({4,2})
Return 6
Which is pretty much the exact same thing the SUMPRODUCT formula would do.
Let me know if there's any further clarification needed.