protected override DbExpression VisitOrderByExpression(DbOrderByExpression orderByExpression)
{
string body = orderByExpression.OrderByExpressionType == DbOrderByExpressionType.Ascending
? "{0} ASC"
: "{0} DESC";
string syntax = string.Format(body, Visit(orderByExpression.Expression));
return ExpressionFactory.Sql(syntax);
}