I have a spreadsheet with two columns, key and name. Right now, the name gets repeated multiple times per value. I set up a formula to get unique values in name, but now I need to get a list of all the values of the cells that match that column.

So if I have the name 'Brian', and there are 4 of them with index values of 5, 6, 7, and 8, I need a formula to take/use the value of C1 to look at B:B and give me all values in A:A.

Is this possible?

In your google-sheets's D1 put this formula in and drag down.

=arrayformula(textjoin(" ", true, if(B:B=C1, A:A, "")))

CONCIF (UDF)

In Excel

=CONCIF($B$1:$B$20,$C1,$A$1:$A$20)

In VBA

Option Explicit

Function CONCIF(MatchRange As Range, ByVal MatchValue As Variant, _
 ConcatRange As Range, _
 Optional ByVal Delimiter As String = " ") As String

 Dim vntM As Variant ' Match Array
 Dim vntC As Variant ' Concat Array
 Dim Nor As Long ' Number of Rows
 Dim i As Long ' Row Counter
 Dim strC As String ' Concat String
 Dim strR As String ' Result String

 ' Check number of rows in MatchRange is less than or equal to number
 ' of rows in Concat Range.
 If MatchRange.Rows.Count <= ConcatRange.Rows.Count Then
 ' Write number of rows in MatchRange to Number of Rows.
 Nor = MatchRange.Rows.Count
 Else
 ' Write number of rows in ConcatRange to Number of Rows.
 Nor = ConcatRange.Rows.Count
 End If

 ' Check if Number of Rows is equal to 1, which would mean there
 ' can only be one match.
 If Nor = 1 Then
 ' Check if the value in 1-cell MatchRange is equal to MatchValue.
 If MatchRange.Cells(1, 1) = MatchValue Then
 ' Write value of 1-cell ConcatRange, converted to string, to CONCIF.
 CONCIF = CStr(ConcatRange.Cells(1, 1))
 End If
 Exit Function
 End If

 ' Copy the range defined by 1st Nor number of cells in 1st column of
 ' MatchRange to 2D 1-based 1-column Match Array.
 vntM = MatchRange.Cells(1, 1).Resize(Nor)
 ' Copy the range defined by 1st Nor number of cells in 1st column of
 ' ConcatRange to 2D 1-based 1-column Concat Array.
 vntC = ConcatRange.Cells(1, 1).Resize(Nor)

 ' Loop through elements (rows) of Match/Concat Arrays.
 For i = 1 To Nor
 ' Check if current value in MatchArray is equal to MatchValue.
 If vntM(i, 1) = MatchValue Then
 ' Write current value in ConcatArray to Concat String.
 strC = CStr(vntC(i, 1))
 ' Check if Concat String is NOT "".
 If strC <> "" Then
 ' Check if Result String is NOT "".
 If strR <> "" Then
 ' Concatenate current value of Result String, Delimiter
 ' and Concat String, to Result String.
 strR = strR & Delimiter & strC
 Else
 ' Write Concat String to Result String (only once).
 strR = strC
 End If
 End If
 End If
 Next

 ' Write Result String to CONCIF.
 CONCIF = strR

End Function