diff --git a/MultiTool.Common/Winline/WinlineData.vb b/MultiTool.Common/Winline/WinlineData.vb
index 8201e7f..893fb40 100644
--- a/MultiTool.Common/Winline/WinlineData.vb
+++ b/MultiTool.Common/Winline/WinlineData.vb
@@ -735,34 +735,43 @@ Namespace Winline
                     oYear = Config.GetWinLineYear(pOptions.Year)
                 End If
 
-                Dim oTypeConstraint
+                Dim oTypeConstraint, oTypeNumberColumn As String
                 Select Case pDocumentType
                     Case DocumentType.OutgoingOffer
                         oTypeConstraint = $"T.c137 = 2 AND c139 = 1 AND "
+                        oTypeNumberColumn = "T.c043"
 
                     Case DocumentType.OutgoingOrder
                         oTypeConstraint = $"T.c137 = 2 AND c139 = 2 AND "
+                        oTypeNumberColumn = "T.c044"
 
                     Case DocumentType.OutgoingDeliveryNote
                         oTypeConstraint = $"T.c137 = 2 AND (c139 = 3 OR c139 = -3) AND "
+                        oTypeNumberColumn = "T.c045"
 
                     Case DocumentType.OutgoingInvoice
                         oTypeConstraint = $"T.c137 = 2 AND c139 = 4 AND "
+                        oTypeNumberColumn = "T.c055"
 
                     Case DocumentType.IncomingOffer
                         oTypeConstraint = $"T.c137 = 3 AND c139 = 1 AND "
+                        oTypeNumberColumn = "T.c043"
 
                     Case DocumentType.IncomingOrder
                         oTypeConstraint = $"T.c137 = 3 AND c139 = 2 AND "
+                        oTypeNumberColumn = "T.c044"
 
                     Case DocumentType.IncomingDeliveryNote
                         oTypeConstraint = $"T.c137 = 3 AND c139 = 3 AND "
+                        oTypeNumberColumn = "T.c045"
 
                     Case DocumentType.IncomingInvoice
                         oTypeConstraint = $"T.c137 = 3 AND c139 = 4 AND "
+                        oTypeNumberColumn = "T.c055"
 
                     Case Else
                         oTypeConstraint = ""
+                        oTypeNumberColumn = ""
                 End Select
 
                 Dim oAccountConstraint = ""
@@ -789,11 +798,20 @@ Namespace Winline
                 End If
 
                 Dim oDocNumberConstraint = ""
-                If pOptions.DocNumberFrom <> String.Empty Then
-                    oDocNumberConstraint &= $"T.c044 >= '{pOptions.DocNumberFrom}' AND "
-                End If
-                If pOptions.DocNumberTo <> String.Empty Then
-                    oDocNumberConstraint &= $"T.c044 <= '{pOptions.DocNumberTo}' AND "
+                If pDocumentType <> DocumentType.Undefined Then
+                    If pOptions.DocNumberFrom <> String.Empty Then
+                        oDocNumberConstraint &= $"{oTypeNumberColumn} >= '{pOptions.DocNumberFrom}' AND "
+                    End If
+                    If pOptions.DocNumberTo <> String.Empty Then
+                        oDocNumberConstraint &= $"{oTypeNumberColumn} <= '{pOptions.DocNumberTo}' AND "
+                    End If
+                Else
+                    oDocNumberConstraint &= $"
+                        (T.c043 >= '{pOptions.DocNumberFrom}' AND T.c043 <= '{pOptions.DocNumberTo}') OR
+                        (T.c044 >= '{pOptions.DocNumberFrom}' AND T.c044 <= '{pOptions.DocNumberTo}') OR
+                        (T.c045 >= '{pOptions.DocNumberFrom}' AND T.c045 <= '{pOptions.DocNumberTo}') OR
+                        (T.c055 >= '{pOptions.DocNumberFrom}' AND T.c055 <= '{pOptions.DocNumberTo}')
+                    "
                 End If
 
                 ' Build the constraint so that the default view will show all documents that do not have an exported
diff --git a/MultiTool.Form/frmExportMain.vb b/MultiTool.Form/frmExportMain.vb
index a80fb2f..22e458d 100644
--- a/MultiTool.Form/frmExportMain.vb
+++ b/MultiTool.Form/frmExportMain.vb
@@ -213,6 +213,10 @@ Public Class frmExportMain
                 .Year = oYear
             })
 
+            If oDocuments Is Nothing Then
+                FormHelper.ShowWarning("There was an error in the Query.")
+            End If
+
             GridControlDocuments.DataSource = oDocuments
 
             txtResults.Caption = String.Format("{0} Ergebnisse", oDocuments.Count)