Date Access 2007-周末

我有一个名为CntDaysdate1，date2的模块

运行此查询时，一切正常：

SELECT MAX(cont.status) as raStatus, 
       MIN(cont.receipt_time) as startDate, 
       MAX(cont.insp_time_c) AS stopDate,
       CntDays(DateValue(MIN(cont.receipt_time)),DateValue(MAX(cont.insp_time_c))) AS days, 
       comments.comments AS comments, 
       comments.exempt AS exempt 
FROM cont, comments
WHERE cont.ra = comments.ra
GROUP BY cont.ra, comments.comments, comments.exempt

但是，如果运行此查询：

SELECT  DISTINCT cont.ra,  
              MAX(cont.status) as raStatus, 
              MIN(cont.receipt_time) as startDate, 
              MAX(cont.insp_time_c) AS stopDate,
              CntDays(DateValue(MIN(cont.receipt_time)),DateValue(MAX(cont.insp_time_c))) AS days, 
              comments.comments AS comments, 
              comments.exempt AS exempt 
FROM cont, comments
WHERE cont.ra = comments.ra
GROUP BY cont.ra, comments.comments, comments.exempt

我一直收到以下错误消息：

          Data type mismatch in criteria expression.

两者之间唯一的区别是不同的cont.ra语句。

---

我没有足够的知识知道如何解决这个问题。

我删除了DISTINCT，它成功了

因此，它是有效的。只是不知道为什么。