public Expression Bind(out SqlColumn column) {
   return Sql.Bind(out column, this);
 }
 public SelectStatement OrderBy(SqlColumn column, OrderByType type) {
   SelectStatement clone = Clone();
   clone.myOrderBy.Add(new OrderByStatement {Column = column, Type = type});
   return clone;
 }
 public UnionExpression OrderBy(SqlColumn column, OrderByType type) {
   var clone = Clone();
   clone.myOrderBy.Add(new OrderByStatement {Column = column, Type = type});
   return clone;
 }