Question

我不知道会调用什么，但我希望只获取特定字段的第一行。然后我想计算行之间的时间。

在这个例子中，每个患者应该只有1个状态1和1个状态2。这是第一部分。然后我想结合（我想的可能是一个不透明的？）并获得时差......

Patient Status  Time Stamp
--------------------------
A       Status1 22:36:45
A       Status2 23:04:13
A       Status2 3:43:13
B       Status1 10:22:42
B       Status2 10:32:47
C       Status1 16:14:30
C       Status2 16:43:41
C       Status2 17:22:49

这是我想要的结果

Patient Time Between Status 1&2 
-------------------------------
A           0:27:28 
B           0:10:05 
C           0:29:11

Answer 1

使用分析函数FIRST_VALUE and LAG：

first_value(time_stamp) OVER(PARTITION BY patient, status ORDER BY time_stamp) first_val

lag(time_stamp) OVER(PARTITION BY patient ORDER BY status) previos_val

然后在first_val和previous_value之间得到区别。

示例（在OracleDB上测试）：

SELECT * FROM (
  SELECT patient, status, time_stamp,
       first_value(time_stamp)
       OVER(PARTITION BY patient, status ORDER BY time_stamp) first_val,
       lag(time_stamp) OVER(PARTITION BY patient ORDER BY status) previos_val
  FROM (
    SELECT 'A' Patient, 'Status1' status,
      to_date('2015-04-07 22:36:45', 'YYYY-MM-DD HH24:MI:SS') time_stamp 
    FROM dual
    UNION ALL
    SELECT 'A' Patient, 'Status2' status,
      to_date('2015-04-07 23:04:13', 'YYYY-MM-DD HH24:MI:SS') time_stamp
    FROM dual
    UNION ALL
    SELECT 'A' Patient, 'Status2' status,
      to_date('2015-04-07 3:43:13', 'YYYY-MM-DD HH24:MI:SS') time_stamp
    FROM dual
  )
)
WHERE time_stamp = first_val
ORDER BY patient, status;

Answer 2

您可以使用ROW_NUMBER（）获取状态1之后的状态2行。

SELECT A.Patient
,CONVERT(varchar(8),CAST(B.TimeStamp as DATETIME)-CAST(A.TimeStamp as DATETIME),8) as Time
FROM yourtable A
JOIN 
(
    SELECT Patient,TimeStamp
    ,ROW_NUMBER() over(partition by Patient ORDER BY Status) as ROWID
    FROM yourtable WHERE Status='Status2'
) B 
ON A.Patient=B.Patient AND B.ROWID=1
WHERE A.Status='Status1'
ORDER BY A.Patient

<强>输出

Patient Time
A       00:27:28
B       00:10:05
C       00:29:11

Answer 3

只需做一个简单的GROUP BY，并计算（第一个）status2和（first）status1之间的差异：

select Patient,
       min(case when Status = 'Status2' then timestamp end) -
          min(case when Status = 'Status1' then timestamp end)
from tablename
group by patient

请注意，我不知道MS SQL Server，因此您可能需要调整时差计算。（看看其他答案！）

在行之间添加时间，仅在SQL Server中占用特定行

3 个答案: