Question

我目前正致力于在Microsoft SQL Server中编写查询。我从中获取数据的表如下所示：

From_State || To_State || Event_Date
------------------------------------
4          || 8        || 2013-12-10 14:15:55.320
8          || 1        || 2013-12-10 14:29:36.823
1          || 4        || 2013-12-10 14:30:10.230
4          || 8        || 2013-12-10 15:56:08.077
8          || 1        || 2013-12-10 21:03:44.053
1          || 4        || 2013-12-10 21:04:17.470

4 =测试，1 =空闲，8 =离线。

我需要通过比较这些时间戳来获得设备测试当天的百分比。我想，除了这一天，查询会计算出设备当天的76％测试结果。

此外，在一天开始时会有一些时间可能会更难以接受，因为它与前一天重叠并且在结束时相同。任何帮助将不胜感激！

Answer 1

想出来，这是我的解决方案：

DECLARE 
      @equipment_id INT = 295, 
      @start_date DATE = '12/01/2013',
      @end_date DATE = '12/11/2013';   

-- Get initial data
WITH data AS 
( 
      -- Ensure rownumber exists to simplify operations
      SELECT ROW_NUMBER() OVER(ORDER BY event_date) AS rownum,
            from_state_id,
            to_state_id,
            event_date
      FROM [triggers].[equipment_state_change] 
      WHERE equipment_id = @equipment_id 
      AND CAST(event_date AS DATE) >= @start_date AND CAST(event_date AS DATE) <= @end_date
), 
-- Determine time differences
data_with_time_differences AS
(
      SELECT 
            thisRecord.rownum, 
            thisRecord.to_state_id,
            thisRecord.event_date,
            CASE WHEN lastRecord.rownum IS NULL OR CAST(lastRecord.event_date AS DATE) < CAST(thisRecord.event_date AS DATE) THEN
                  DATEDIFF(mi, CAST(thisRecord.event_date AS DATE), thisRecord.event_date)
                 WHEN CAST(thisRecord.event_date AS DATE) < CAST(nextRecord.event_date AS DATE) THEN
                  DATEDIFF(mi, thisRecord.event_date, CAST(nextRecord.event_date AS DATE))
            ELSE
                  DATEDIFF(mi, lastRecord.event_date, thisRecord.event_date)
            END AS minutes_in_state,
            -- Mark Records that will be used for % calculation as 4
            CASE WHEN CAST(thisRecord.event_date AS DATE) < CAST(nextRecord.event_date AS DATE) AND thisRecord.to_state_id = 4 THEN
                   4
                 ELSE
                   thisRecord.from_state_id
            END AS recordToCalculateFrom
      FROM data thisRecord
      LEFT JOIN data lastRecord ON lastRecord.rownum = thisRecord.rownum - 1
      LEFT JOIN data nextRecord ON nextRecord.rownum = thisRecord.rownum + 1
)

SELECT SUM(CAST(minutes_in_state AS FLOAT)) /60 /24 * 100 as PercentageOfDayTesting, CAST(event_date AS DATE) as Date
from data_with_time_differences
where recordToCalculateFrom = 4
group by CAST(event_date AS DATE)
order by Date

这是我的预期结果。也许这会帮助那里的人。如果不清楚我在做什么，请随意提问。

比较SQL中单独行的日期

1 个答案: