sql_test1 = "SELECT DISTINCT Grafik_A From Tabelle_A Union SELECT DISTINCT" & _
  "Grafik_B AS Grafik_A FROM Tabelle_B Union SELECT DISTINCT Grafik_C AS" & _
  "Graphik_A FROM Tabelle_C"
 
If OpenRecordset(mRs, mConn, sql_test1, adOpenStatic, adUseClient, _
   adLockOptimistic) Then
 
   Do Until mRs.EOF
   Combo1.AddItem mRs.Fields("Grafik_A")
   mRs.MoveNext
   Loop
 
 End If