SELECT COUNT(*) FROM Liste WHERE (Name = '')

Dim SqlString As  String = "Insert Into Contacts (FirstName, LastName) Values (" & _
  "?,?)"
    cmd.CommandType = CommandType.Text
    cmd.Parameters.AddWithValue("FirstName", txtFirstName.Text)
    cmd.Parameters.AddWithValue("LastName", txtLastName.Text)

 
        SQL.CommandText = "SELECT COUNT(*) FROM Liste " & _
                                "WHERE (Name = ?)" & _
                                " AND (Nachname = ?)" & _
                                " AND (Adresse = ?)"
        'Parameter Definieren
        SQL.CommandType = CommandType.Text
 
        'Parameter Füllen
if Varname = "" then
        SQL.Parameters.AddWithValue("Name", DBNull.Value)
else
        SQL.Parameters.AddWithValue("Name", VarName)
End If
 
If VarNachname = "" then
        SQL.Parameters.AddWithValue("Nachname", DBNull.Value)
else
        SQL.Parameters.AddWithValue("Nachname", VarNachname)
End If
 
If VarAdresse = "" then
        SQL.Parameters.AddWithValue("Adresse", DBNull.Value)
else
        SQL.Parameters.AddWithValue("Adresse", VarAdresse)
End If