select records with Unique values in certain fieldsth (1 Viewer)

Public Sub fRSL_LastPost()
'RSL = Record Set Loop
Dim strSubName As String
Dim strModuleName As String

strSubName = "fRSL_LastPost"
strModuleName = "Form - " & Me.Name
'strModuleName = "basModNameHere"

On Error GoTo Error_Handler
    
    Dim curDB As DAO.Database
    Dim rst As DAO.Recordset

    Set curDB = CurrentDb
    

'SELECT ID, MTH, YEAR, POST, Flg
'FROM tblLastPost


Dim strSQL_RSL As String
strSQL_RSL = "SELECT ID, MTH, YEAR, POST, Flg FROM tblLastPost"

    Dim strLastPost As String
    Dim lngCounter As Long
   
            Set rst = curDB.OpenRecordset(strSQL_RSL, dbOpenDynaset)
               
                    Do Until rst.EOF
                        
                        'First Pass Only
                        If lngCounter = 0 Then
                        
                            rst.Edit
                            rst!Flg = True
                            rst.Update
                            strLastPost = rst!POST
                        
                        Else
                        
                            If rst!POST <> strLastPost Then
                                rst.Edit
                                rst!Flg = True
                                rst.Update
                                strLastPost = rst!POST
                            End If
                            
                        End If
                        lngCounter = lngCounter + 1
                        rst.MoveNext
                    Loop
    
Exit_ErrorHandler:
        rst.Close
    Set rst = Nothing
    Set curDB = Nothing
    
    Exit Sub

Error_Handler:  'Version - 1a
    Dim strErrFrom As String
    Dim strErrInfo As String
        
        strErrFrom = "Error From:-" & vbCrLf & strModuleName & vbCrLf & "Subroutine >>>>>>> " & strSubName
        strErrInfo = "" & vbCrLf & "Error Number >>>>> " & Err.Number & vbCrLf & "Error Descscription:-" & vbCrLf & Err.Description
            
            Select Case Err.Number
                 Case 1 'When Required, Replace Place Holder (1) with an Error Number
                    MsgBox "Error produced by Place Holder please check your code!" & vbCrLf & vbCrLf & strErrFrom & strErrInfo
                Case Else
                    MsgBox "Case Else Error" & vbCrLf & vbCrLf & strErrFrom & strErrInfo
            End Select
        Resume Exit_ErrorHandler

End Sub     'fRSL_LastPost

Public Function fnLocation() As String
    Dim db As dao.Database
    Dim rs As dao.Recordset
    Dim strlocation As String

    Set db = CurrentDb
    Set rs = db.OpenRecordset("select [Year] & [Month], [posting place] from yourTable;", dbOpenSnapshot)
    With rs
        If Not (.BOF And .EOF) Then .MoveFirst
        strlocation = rs(1)
        fnLocation = rs(0)
        .MoveNext
        While Not .EOF
            If strlocation <> rs(1) Then
                strlocation = rs(1)
                fnLocation = fnLocation & "/" & rs(0)
            End If
            .MoveNext
        Wend
        .Close
    End With
    Set rs = Nothing
    Set db = Nothing
End Function