Find distinct values based upon multiple columns - excel

Question

I have a spreadsheet of sales with (to keep the example simple) 3 columns
NAME -- STATE -- COUNTRY
It's easy to find how many sales. (sum all the lines)
I can find out how many customers I have but how about finding out how many customers from a particular state (and country)
NAME -- STATE -- COUNTRY
p1----- CA------ USA
p2----- CA------ USA
p1----- CA------ USA
p1----- CA------ USA
p3----- NY------ USA
p3----- NY------ USA
The above example would give 2 unique customers from CA and 1 unique customer from NY and 3 from the USA
EDIT:
The desired result from the above table would be
STATE - UNIQUE CUSTOMERS
CA ---- 2
NY ---- 1
COUNTRY - UNIQUE CUSTOMERS
USA ---- 3

Answer 1

Assuming your data have headers in row 1 of columns A, B, and C, follow these directions.
In cell F1 enter STATE.
In cell G1 enter COUNT.
In cell F2 enter this array-formula (must be confirmed with Ctrl+Shift+Enter↵):
=IFERROR(INDEX(B$2:INDEX(B:B,COUNTA(B:B)),MATCH(0,COUNTIF(F$1:F1,B$2:INDEX(B:B,COUNTA(B:B))),)),"")
In cell G2 enter this regular formula (confirmed with Enter):
=IF(LEN(F2),COUNTIF(B2:B13,F2),"")
Select F2:G2 and copy.
Now select F3:F51 and paste.
UPDATE
The nature of the question changed. The first formula is exactly the same as before. It gets the distinct states in the source data and culls them so they display with no blanks.
The second formula is now different. It needs to count the number of distinct customers in each state, and it is now an array formula confirmed with Ctrl+Shift+Enter↵).
=IF(LEN(F2),SUM(IF(F2=$B$2:$B$50,1/(COUNTIFS($B$2:$B$50,F2,$A$2:$A$50,$A$2:$A$50)),)),"")

Answer 2

This formula (entered as an array formula CTRL-SHIFT-ENTER) will count the number of occurrences of a Name in MyState
=COUNTIFS(Names,Names,States,MyState)
So if MyState="CA" this would return {3;1;3;3;0;0}
To get the number of names in CA you can sum the reciprocals of this array, EXCEPT taking the reciprocal of zero is invalid/infinite. So wrap the formula above in a test for zero: if it's zero, output zero, otherwise take the reciprocal (one of the rare situations where you get to set infinity equal to zero!):
=IF(COUNTIFS(Names,Names,States,MyState)=0,0,1/COUNTIFS(Names,Names,States,MyState))
(Still an array formula.)
For CA this will return {0.333333;1;0.333333;0.333333;0;0}
The final step is to sum with the array formula:
=SUM(IF(COUNTIFS(Names,Names,States,MyState)=0,0,1/COUNTIFS(Names,Names,States,MyState)))
It's possible that this could return say 2.99999... instead of 3 due to rounding errors. If that's a problem you can fix it by wrapping it with the ROUND function or setting the display format zero decimal places.
It should be straightforward to modify this to count by country. Hope that helps.

Answer 3

Since the question also has an 'google-spreadsheets' tag, this would be my suggested formula to use in a google spreadsheet:
For the state counts:
=query(unique(ArrayFormula({A2:A&B2:B, A2:C})), "select Col3, count(Col1) where Col3 <> '' group by Col3 label count(Col1)''",0)
And for the country counts:
=query(unique(ArrayFormula({A2:A&B2:B&C2:C, C2:C})), "select Col2, count(Col1) where Col2 <> '' group by Col2 label count(Col1)''",0)
Also see this example spreadsheet.

Answer 4

Easy with a PivotTable in Excel 2013:
Also easy with Google Spreadsheets: