SQL Server 2008重复行和平均值

Question

我正在尝试从具有相同ID的行重复的表中获取平均值和最后一个日期行，例如：

Table:
ID  VisitID     Date            Value
1   1       10-10-2001      1
2   1       10-11-2001      1
1   2       10-11-2001      3
OUT PUT
Table:
ID  VisitID     Date                Value
1   1       10-11-2001 ***(max date)***     2  (***total of the two date / number of rows)***
2   1       10-11-2001          1

提前致谢。

Answer 1

SELECT ID 
,VisitID = MIN(VisitID)
,Date = MAX(Date)
,Value= COUNT(*)
FROM Table
GROUP BY ID

是我认为你想要的，除非我错过了这个问题。

Answer 2

SELECT ID, MIN(VisitID) as VisitID, Date, AVG(Value) as Value
FROM Table
GROUP BY ID, Date