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index 5090352..b2e8168 100644
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diff --git a/Projekt_Calcan_Conze/Projekt_Calcan_Conze_Export/Repositories/Database.cs b/Projekt_Calcan_Conze/Projekt_Calcan_Conze_Export/Repositories/Database.cs
index 7d769ff..fac00f5 100644
--- a/Projekt_Calcan_Conze/Projekt_Calcan_Conze_Export/Repositories/Database.cs
+++ b/Projekt_Calcan_Conze/Projekt_Calcan_Conze_Export/Repositories/Database.cs
@@ -126,21 +126,24 @@ internal static class Database
 
                 // set wasBilled to 1 for all retrieved activities
 
-                string activityIdsString = string.Join(',', activityIds.Select((_, i) => $"@activityId{i}"));
-                var updateWasBilledCommand =
-                    new MySqlCommand
-                    {
-                        Connection = dbConnection,
-                        Transaction = transaction,
-                        CommandText = $"UPDATE activity SET wasBilled = 1 WHERE id IN ({activityIdsString})"
-                    };
-
-                for (int i = 0; i < activityIds.Count; i++)
+                if (activityIds.Any())
                 {
-                    updateWasBilledCommand.Parameters.AddWithValue($"@activityId{i}", activityIds[i]);
-                }
+                    string activityIdsString = string.Join(',', activityIds.Select((_, i) => $"@activityId{i}"));
+                    var updateWasBilledCommand =
+                        new MySqlCommand
+                        {
+                            Connection = dbConnection,
+                            Transaction = transaction,
+                            CommandText = $"UPDATE activity SET wasBilled = 1 WHERE id IN ({activityIdsString})"
+                        };
 
-                await updateWasBilledCommand.ExecuteNonQueryAsync();
+                    for (int i = 0; i < activityIds.Count; i++)
+                    {
+                        updateWasBilledCommand.Parameters.AddWithValue($"@activityId{i}", activityIds[i]);
+                    }
+
+                    await updateWasBilledCommand.ExecuteNonQueryAsync();
+                }
             }
             catch (Exception)
             {