VLOOKUP MATCH with returning multiple values

Question

ColumnA (All customers)     ColumnB (E-mail)     ColumnC (Specific customers)

CustNO                      MailAddress          CustNO
1                           test@test.com        2
2                           test2@test2.com      1
                            test3@test3.com      1

I am using the following function to return the value of ColumnB when the value of ColumnA matches in a row of ColumnC:

=VLOOKUP(C2;A2:A520;MATCH(B1;A1:C1))

The problem is, that ColumnC can contain multiple values of ColumnA as shown in the above example.

The function as above is only returning the value of ColumnB, for only the first match found of ColumnA and ColumnC. Any idea how I can return all of the values for also the multiple returning values, as shown in above example, ColumnC contains multiple rows with CustNO 1.

Answer 1

you need to use the index and small functions to extract the 1st, 2nd, 3rd ... matching values.

=IFERROR(INDEX($A$2:$C$250,SMALL(IF(($A2:$A$250=$C$2),ROW($A$2:$A$250)-1),ROW(1:1)),2),"")

IMPORTANT: use CTRL + SHIFT + ENTER when entering this formula to make it an array formula.

note that this formula uses ROW(1:1) to extract the first match, this will change to 2:2, 3:3 etc as to auto fill down.

I don't know from your question where you want to display the results but I would suggest that you take the unique values from column C and and transpose them across the top of a new sheet and then put the lookup formula below each value so you have a list of email addresses for each customer number.