Private Sub Command1_Click()
Dim aConn As ADODB.Connection
Set aConn = New ADODB.Connection
aConn.ConnectionString = "DSN=XYZ;"
aConn.Open
 
Dim rs As ADODB.Recordset
Dim sSQL As String
sSQL = "SELECT col1, col2 FROM t1 " & _
    "GROUP BY col1, col2 " & _
    "HAVING COUNT(*) > 1"
 
Set rs = New ADODB.Recordset
Call rs.Open(sSQL, aConn)
Do While Not rs.EOF
   MsgBox "More than one record with columnvalues  Col1:" & rs(0) & " Col2:" & rs(1)
   rs.MoveNext
Loop
rs.Close
 
End Sub

Private Sub Command2_Click()
Dim aConn As ADODB.Connection
Set aConn = New ADODB.Connection
aConn.ConnectionString = "DSN=VPE;"
aConn.Open
Dim rs1 As ADODB.Recordset
Dim rs2 As ADODB.Recordset
Dim sDups As String
Dim sSQL1 As String
Dim sSQL2 As String
Dim iCnt As Integer
 
sDups = ""
iCnt = 0
sSQL1 = "SELECT keycol, fprintcol FROM table1 ORDER BY keycol"
Set rs1 = New ADODB.Recordset
Call rs1.Open(sSQL1, aConn)
Do While Not rs1.EOF
   sSQL2 = "SELECT keycol, fprintcol FROM table1 WHERE keycol <> '" & rs1!keycol & "'"
   Set rs2 = New ADODB.Recordset
   Call rs2.Open(sSQL2, aConn)
   Do While Not rs2.EOF
      'comparing, for example:
      If rs2!fprintcol = rs1!fprintcol Then 
          'do not remember the same key multiple times
          If InStr(sDups, "|" & Trim(rs1!keycol)) = 0 Then
              sDups = sDups & "|" & Trim(rs1!keycol)
              iCnt = iCnt + 1
          End If
      End If
      rs2.MoveNext
   Loop
   rs1.MoveNext
Loop
MsgBox Replace(sDups, "|", vbLf)
End Sub