NBearLite_v1.0.2.5 使用GROUPBY的疑问：

我想要的查询是：
SELECT [Work_holiday_order].[Center_name]
FROM [Work_holiday_order]
WHERE holiday_begin_time>='2008/11/01'
GROUP BY [Work_holiday_order].[Center_name]



程序上是这样写查询的：
                db.Select(FSJSJ.Work_holiday_order, FSJSJ.Work_holiday_order.Center_name)
                 .Where(FSJSJ.Work_holiday_order.holiday_begin_time >= YearANDmonth_begin)
                 .GroupBy(FSJSJ.Work_holiday_order.Center_name)
                 .ToDataSet();

可是NBearLite_v1.0.2.5生成的SQL语句是这样的：

SELECT [Work_holiday_order].[Center_name]
FROM [Work_holiday_order]
GROUP BY [Work_holiday_order].[Center_name]
HAVING  holiday_begin_time>='2008/11/01'



是我语句写错了，还是Bug????