private static void InnerGetFields(IConnectiveSqlClause connective, HashSet <string> fields)
{
HashSet <string> innerFields = connective.GetFields();
foreach (string field in innerFields)
{
if (fields.Contains(field) == false)
{
fields.Add(field);
}
}
foreach (IConnectiveSqlClause subConnective in connective.GetSubConnectiveSqlClause())
{
InnerGetFields(subConnective, fields);
}
}