public override ODataExpression VisitOrderBy(ODataOrderByExpression expr)
 {
     foreach (ODataOrderByExpression.Selector s in expr.Selectors)
     {
         this.Visit(s.Expression);
         this.sqlBuilder.Append(" " + s.Order.ToString().ToUpperInvariant() + " ");
     }
     // remove last space
     this.sqlBuilder.Remove(this.sqlBuilder.Length - 1, 1);
     return expr;
 }
 public virtual ODataExpression VisitOrderBy(ODataOrderByExpression expr)
 {
     return this.Visit(expr);
 }