How to SUM a column of values in Sheet A IF a different column of values IS EQUAL TO a column of values in Sheet B

Question

I am working with Google Sheets/Excel. In Sheet A, I have the names of customers who have purchased various items, along with the cost of those items.

Sheet A

Column A	Column B	Column C
Customer A	Toothbrush	$1.00
Customer B	Pencil	$2.00
Customer C	Tent	$5.00
Customer C	Juice	$4.00

In Sheet B, I want to calculate the total amount of money spent by each customer, by referencing their name from Sheet A.

Sheet B

Column A	Column B
Customer A	$1.00
Customer B	$2.00
Customer C	$9.00

This is what I have tried so far. I put these formulas into Sheet B, Column B:

=COUNTIF(A:A,"='Sheet A'!A:A")

=SUMPRODUCT('Sheet A'!C:C,COUNTIF(A:A,"='Sheet A'!A:A))"))

Answer 1

In google-sheet you can use QUERY() function like

=QUERY(A1:C4,"Select A, Sum(C) Group By A Label A 'Customer', Sum(C) 'Sum'")

If you want result in Sheet2 then use below

=QUERY(Sheet1!A1:C4,"Select A, Sum(C) Group By A Label A 'Customer', Sum(C) 'Sum'")

In Excel-365 I use below formulas

E2=UNIQUE(A1:A4)
F2=SUMIFS($C$1:$C$4,$A$1:$A$4,E2#)