Question

我必须为火车站的登机口生成一个简单的正常运行时间报告。如果任何门有任何错误，则该错误在数据库中具有特定原因，并且startTime和EndTime中断。有几种情况需要照顾：

如果一个站上有2个登机口，那么一个登机口在每月的前15天工作，第二个登机口工作，或者在接下来的15天内工作，因此两个登机口中的一个都在工作。因此，该站的值应为100％。如果两个天数都下降了，那么这个百分比就不会出现。

我已经写下了一个查询，但是执行数十万条记录需要5-6分钟的时间，因此它会阻塞系统。

declare @dt_start datetime, @dt_end datetime
set @dt_start = '2019-04-01 00:00';
set @dt_end = '2019-04-30 23:59';
DROP TABLE IF EXISTS #minutesTime;
with cte_Dates as (
        SELECT @dt_start as uptimeMinute
        UNION ALL
        SELECT DATEADD(MINUTE,1,uptimeMinute)
        FROM cte_Dates
        WHERE DATEADD(MINUTE,1,uptimeMinute) < @dt_end
    )

SELECT * 
INTO #minutesTime FROM cte_Dates
WHERE CAST(uptimeMinute as time) >= '05:00:00'
or CAST(uptimeMinute as time) < '02:00:00'
OPTION(MAXRECURSION 0);

SELECT
uptimeMinute,
count(DISTINCT o.ReaderID) as numOfflineReaders
FROM #minutesTime m
CROSS JOIN Readers r 
JOIN Outages o
ON r.ReaderId = o.ReaderId
WHERE 
uptimeMinute BETWEEN o.OutageStart AND o.OutageEnd
GROUP BY 
uptimeMinute having count(DISTINCT o.ReaderID)=3
ORDER BY 
uptimeMinute;

表定义为：

读者：

ReaderId NotificationsDisabled
1        0
2        1

中断：

OutageId    SourceType  SourceId    OutageStart                     OutageEnd                       OutageSeconds   ReaderId
1           Faults          1       2019-03-28 10:13:35.6700000     2019-03-31 00:21:45.5900000     223690          24

Answer 1

“日期”构建器（使用递归）可能效率低下。您可以尝试以下方法：

DECLARE @StartDate DATETIME = '2019-04-01 00:00'  , @EndDate DATETIME= '2019-04-30 23:59';



WITH dates as (
SELECT  DATEADD(MINUTE, nbr - 1, @StartDate) as uptimeMinute
FROM    ( SELECT    ROW_NUMBER() OVER ( ORDER BY c.object_id , c.a ) AS Nbr
          FROM      
          (SELECT c.object_id, 1 as a FROM sys.columns c
          UNION ALL 
          SELECT c.object_id, 0 as a FROM sys.columns c) c
        ) nbrs
WHERE   nbr - 1 <= DATEDIFF(MINUTE, @StartDate, @EndDate)
)
SELECT uptimeMinute into #minute
from dates
WHERE CAST(uptimeMinute as time) >= '05:00:00'
or CAST(uptimeMinute as time) < '02:00:00'

优化报表的SQL查询

1 个答案: