public override void EnterOrderByStmt(SelectSQLParser.OrderByStmtContext context)
{
var orderBy = new OrderByCondition();
var expression = context.columnExpression();
if (expression == null || expression.IsEmpty)
throw new MissingOrderByException();
orderBy.Expression = expression.GetText();
if (string.IsNullOrEmpty(orderBy.Expression))
throw new MissingOrderByException();
orderBy.Direction = OrderByDirection.DESC;
var direction = context.orderByDirection();
if (direction == null || direction.IsEmpty)
orderBy.Direction = OrderByDirection.ASC;
else if(direction.GetText().Equals("asc", StringComparison.OrdinalIgnoreCase))
orderBy.Direction = OrderByDirection.ASC;
this.SelectStmt.OrderBy.Add(orderBy);
}
