如何使用逻辑条件在现有表上创建查询并生成包含bool数据的表(视图)？
如何使用逻辑条件在现有表上创建查询并生成包含bool数据的表(视图)？
提问于 2015-06-23 13:18:29
我所拥有的是一个MS数据库，用于存储来自于安装在某些车辆中的设备的数据/信息(每辆车有1-3台设备)。
目前，数据库中有一个名为Communication的表--一个用于存储设备连接到TCP服务器时来自设备的所有信息的大表。一个接一个地添加记录(只在这里插入)。
这张桌子是这样的：
我需要的是一个SQL查询(命令/语句)来为所谓的“每周通信状态”创建一个表(视图)，在这里我可以看到如果/车辆在过去7天中如何通信.如下表所示：
回答 2
Stack Overflow用户
回答已采纳
发布于 2015-06-23 13:46:35
作为上述选项的另一种选择，您知道输出中只有7个日期列，您可以使用手动转轴，而不是使用pivot运算符。
请参阅SQLFiddle
select VehicleNumber,
CASE WHEN SUM(CASE WHEN DATEDIFF(d,DateTimeCommunication, DATEADD(d,-7,GETDATE())) = 0 THEN 1 ELSE 0 END) > 0 THEN 'YES' Else 'NO' END AS [7 Days Ago]
,CASE WHEN SUM(CASE WHEN DATEDIFF(d,DateTimeCommunication, DATEADD(d,-6,GETDATE())) = 0 THEN 1 ELSE 0 END) > 0 THEN 'YES' Else 'NO' END AS [6 Days Ago]
,CASE WHEN SUM(CASE WHEN DATEDIFF(d,DateTimeCommunication, DATEADD(d,-5,GETDATE())) = 0 THEN 1 ELSE 0 END) > 0 THEN 'YES' Else 'NO' END AS [5 Days Ago]
,CASE WHEN SUM(CASE WHEN DATEDIFF(d,DateTimeCommunication, DATEADD(d,-4,GETDATE())) = 0 THEN 1 ELSE 0 END) > 0 THEN 'YES' Else 'NO' END AS [4 Days Ago]
,CASE WHEN SUM(CASE WHEN DATEDIFF(d,DateTimeCommunication, DATEADD(d,-3,GETDATE())) = 0 THEN 1 ELSE 0 END) > 0 THEN 'YES' Else 'NO' END AS [3 Days Ago]
,CASE WHEN SUM(CASE WHEN DATEDIFF(d,DateTimeCommunication, DATEADD(d,-2,GETDATE())) = 0 THEN 1 ELSE 0 END) > 0 THEN 'YES' Else 'NO' END AS [2 Days Ago]
,CASE WHEN SUM(CASE WHEN DATEDIFF(d,DateTimeCommunication, DATEADD(d,-1,GETDATE())) = 0 THEN 1 ELSE 0 END) > 0 THEN 'YES' Else 'NO' END AS [1 Days Ago]
,CASE WHEN SUM(CASE WHEN DATEDIFF(d,DateTimeCommunication, GETDATE()) = 0 THEN 1 ELSE 0 END) > 0 THEN 'YES' Else 'NO' END AS [0 Days Ago]
from Communications
GROUP BY VehicleNumberStack Overflow用户
发布于 2015-06-23 13:27:34
下面是一种动态PIVOT方法。
CREATE TABLE #temp(equipmentID int, vehicleNumber int, DateTimeCommunication datetime)
INSERT INTO #temp(equipmentID, vehicleNumber, DateTimeCommunication)
VALUES (1,100,GETDATE()),
(2,110,GETDATE()),
(3,120,GETDATE()),
(5,140,GETDATE()),
(1,100,DATEADD(day,-8,GETDATE())),
(3,120,DATEADD(day,-8,GETDATE())),
(4,130,DATEADD(day,-8,GETDATE())),
(5,140,DATEADD(day,-8,GETDATE()))
DECLARE @sql nvarchar(max), @columns nvarchar(max), @columnsSelect nvarchar(max)
SELECT @columns = COALESCE(@columns + N',['+CONVERT(nvarchar(max),dateCom)+N']',N'['+CONVERT(nvarchar(max),dateCom)+N']')
FROM (
SELECT DISTINCT CONVERT(date, DateTimeCommunication) as dateCom
FROM #temp
) as allDates
ORDER BY dateCom
SELECT @columnsSelect = COALESCE(@columnsSelect + N',ISNULL(['+CONVERT(nvarchar(max),dateCom)+N'],N''NO'') as '''+CONVERT(nvarchar(max),dateCom)+'''',
N'ISNULL(['+CONVERT(nvarchar(max),dateCom)+N'],N''NO'') as '''+CONVERT(nvarchar(max),dateCom)+'''')
FROM (
SELECT DISTINCT CONVERT(date, DateTimeCommunication) as dateCom
FROM #temp
) as allDates
ORDER BY dateCom
SET @sql = N'SELECT pvt.vehicleNumber, '+@columnsSelect+'
FROM (
SELECT t.equipmentID, t.vehicleNumber, CONVERT(date,DateTimeCommunication) as dateCom,
CASE WHEN t.DateTimeCommunication BETWEEN DATEADD(day,-7,GETDATE()) AND GETDATE()
THEN N''YES''
ELSE N''NO''
END as communicated
FROM #temp t
) as dat
PIVOT(
MAX(communicated)
FOR dateCom IN('+@columns+')
) as pvt'
PRINT(@sql)
EXEC (@sql)
DROP TABLE #temp如果您不需要动态的或仅针对指定的日期范围，只需将其简化为：
CREATE TABLE #temp(equipmentID int, vehicleNumber int, DateTimeCommunication datetime)
INSERT INTO #temp(equipmentID, vehicleNumber, DateTimeCommunication)
VALUES (1,100,GETDATE()),
(2,110,GETDATE()),
(3,120,GETDATE()),
(5,140,GETDATE()),
(1,100,DATEADD(day,-8,GETDATE())),
(3,120,DATEADD(day,-8,GETDATE())),
(4,130,DATEADD(day,-8,GETDATE())),
(5,140,DATEADD(day,-8,GETDATE()))
SELECT *
FROM (
SELECT t.equipmentID, t.vehicleNumber, CONVERT(date,DateTimeCommunication) as dateCom,
CASE WHEN t.DateTimeCommunication BETWEEN DATEADD(day,-7,GETDATE()) AND GETDATE()
THEN N'YES'
ELSE N'NO'
END as communicated
FROM #temp t
) as dat
PIVOT(
MAX(communicated)
FOR dateCom IN([2015-06-23]) --needs to be changed on different date!
) as pvt
DROP TABLE #temp页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/31003902
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