2010-01-17 135 views
0

下面是一个有效的SQL查询,用于计算具有重叠的时间差异。
由于某些原因,我需要创建一个视图 - 因此我不能使用临时表TempALMDB。相反,视图以SELECT X.Alarmgroup开始,我必须使用已经创建的视图QV_Alarms。但在这种情况下,输出与临时表的版本不同。重叠---没有临时表结果的时间范围是错的

原始视图包含以下colums: Alarmgroup,AlarmON,AlarmOFF,优先级,...

AlarmOn和AlarmOFF是报警的到达和返回时间。计算是为每个报警组完成的。为了减少每个查询的计算时间,我包括Alarmgroup和Priority(在临时表中)的WHERE子句。第二部分也可以为小组讨论。

我的问题:
1.当我仅使用第2部分(用QV_Alarms替换了4次TempALMDB)时,为什么会得到不同的错误结果?
2.如何在第2部分中包含优先级的WHERE子句?

-- PART 1: Temporary table 
IF EXISTS(SELECT * FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_NAME = 'TempALMDB') 
DROP TABLE TempALMDB 

Select TOP 500 Alarmgroup, AlarmON, AlarmOff INTO TempALMDB FROM QV_Alarms 
WHERE Alarmgroup = 'A1_1_Alarms' 
ORDER BY Alarmgroup, AlarmON 

--PART 2: Time difference calculation 
SELECT X.Alarmgroup, X.Coming, X.Going, Datediff(minute, X.Coming, X.Going) 
AS minutes FROM (
    SELECT G2.Alarmgroup, Min(G2.Start1) AS Coming, Max(G2.Going1) 
    AS Going FROM (
    SELECT G1.Alarmgroup, Min(G1.Start2) AS Start1, Max(G1.Going2) 
    AS Going1 FROM (
     SELECT T1.Alarmgroup, Min(T1.AlarmON) AS Start2, Max(T1.AlarmOff) 
     AS Going2 FROM TempALMDB AS T1 INNER JOIN TempALMDB AS T2 
     ON (T1.Alarmgroup = T2.Alarmgroup AND T1.AlarmON < T2.AlarmOff 
     AND T1.AlarmOff > T2.AlarmON AND NOT (T1.AlarmON = T2.AlarmON 
     AND T1.AlarmOff = T2.AlarmOff)) 
     GROUP BY T1.Alarmgroup, 
     CASE WHEN T1.AlarmON BETWEEN T2.AlarmON AND T2.AlarmOff 
     THEN T2.AlarmON ELSE T1.AlarmON END, 
     CASE WHEN T1.AlarmOff BETWEEN T2.AlarmON AND T2.AlarmOff 
     THEN T2.AlarmOff ELSE T1.AlarmOff END 
    ) AS G1 
    GROUP BY G1.Alarmgroup, G1.Going2) AS G2 
    GROUP BY G2.Alarmgroup, G2.Start1 

UNION ALL 

SELECT U1.Alarmgroup, U1.AlarmON, U1.AlarmOff 
FROM TempALMDB AS U1 LEFT JOIN TempALMDB AS U2 
ON (U1.Alarmgroup = U2.Alarmgroup AND U1.AlarmON < U2.AlarmOff 
AND U1.AlarmOff > U2.AlarmON 
AND NOT (U1.AlarmON = U2.AlarmON AND U1.AlarmOff = U2.AlarmOff)) 
WHERE U2.Alarmgroup IS NULL 
) AS X 
WHERE X.Alarmgroup = 'A1_1_Alarms' 
ORDER BY X.Alarmgroup, X.Coming, X.Going 

回答

0

您是否尝试过用第二部分替换TempALMDB的所有实例?

(Select TOP 500 Alarmgroup, AlarmON, AlarmOff FROM QV_Alarms 
WHERE Alarmgroup = 'A1_1_Alarms' 
ORDER BY Alarmgroup, AlarmON) 
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