我有以下查询：

INSERT into @TEST (col1,staffnumber,rn)
SELECT starttime as col1,staffnumber,ROW_NUMBER() OVER (PARTITION BY StaffNumber ORDER BY STARTTIME DESC) AS rn
  FROM @TempTable2 t2
UNION 
SELECT eventdate as col1, staffnumber,ROW_NUMBER() OVER (PARTITION BY StaffNumber ORDER BY EVENTDATE DESC) AS rn
  FROM @TempTable1 t1

但是，显然，这给了我以下值：

COL1                | staffnumber    | rn
10/02/2014 10:29:24         1          1
10/02/2014 09:08:19         1          3
10/02/2014 10:00:23         1          2
10/02/2014 10:00:29         1          1

而我需要它来显示：

COL1                | staffnumber    | rn
10/02/2014 10:29:24         1          1
10/02/2014 09:08:19         1          4
10/02/2014 10:00:23         1          3
10/02/2014 10:00:29         1          2

我可以通过执行以下操作来做到这一点：

INSERT into @TEST1 (col1,staffnumber,rn)
SELECT convert(time,col1),staffnumber,ROW_NUMBER() OVER (PARTITION BY StaffNumber ORDER BY convert(time,COL1) DESC) AS rn
FROM @TEST

但是必须有一种更简单，更有效的方法。有任何想法吗？