为什么小弟我的Left Join 无效，求大神看看小弟我的SQL 应该如何写

为什么我的Left Join 无效，求大神看看我的SQL 应该怎么写
客户表 Customer
Id      客户编号     Name 客户名称
A01                            张三
A02                            李四
A03                            王五

订单统计表 OrderGroup
Id 订单统计编号  CustomerId 客户编号  OrderDate 订单统计日期  CurrentDatePrice 当日订单总金额  CurrentDateCount 当日订单总数
1                                 A01                                   20140812                                 100                                                  4
2                                 A02                                   20140812                                   50                                                   2
3                                 A03                                   20140811                                   43                                                   1

订单统计表的结构为， 一个客户一天 只存在一条记录,如果在当天下了多个订单，在订单统计表中只累计当日订单总金额和当日订单总数 ,也有可能客户在今天没有下订单， 那么查询出来这个客户今日的统计就是null ,所以我用了left join查询 ,SQL语句如下

select c.Id,c.Name,og.OrderDate,og.CurrentDatePrice,og.CurrentDateCount from 
Customer as c left join OrderGroup as og on c.CustomerId=og.CustomerId and OrderDate='20140812'

我想要得到的结果数据为
A01                                 张三                                   20140812                                 100                                                  4
A02                                 李四                                   20140812                                   50                                                   2