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我正在尝试在 Wonderware 中的表中查询某些数据。我知道查询的“a”部分中有一些数据，其 TagName 等于“Weightdata2.uiID”。但是“b”部分没有匹配的数据，因此查询返回空数据集。但是，如果那里没有匹配的数据，我想在 uiWater 列中获取 'a' 部分和 'b' 的数据，其中 NULL 或零。

这是我的查询：

DECLARE @StartDate DateTime
DECLARE @EndDate DateTime
set @StartDate = '2018-09-18 08:00:00.000'
set @EndDate = '2018-09-18 09:00:00.000'

SELECT a.Value as uiID, b.value as uiWater, cast(a.datetime as datetime2(0)) 
as dtCreated, 2 as Weightdata
FROM [INSQL].[Runtime].[dbo].[History] a
JOIN [INSQL].[Runtime].[dbo].[History] b ON a.datetime=b.datetime
WHERE a.TagName IN ('Weightdata2.uiID') and a.datetime>=@StartDate and 
a.datetime<=@EndDate and a.Value!=0
and b.TagName IN ('Weightdata2.uiWater') and b.datetime>=@StartDate and 
b.datetime<=@EndDate

我想要这样的结果

4

3 回答 3

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您只需将 JOIN 替换为 LEFT JOIN。如果值为 null，您可以使用 isnull 返回 0

DECLARE @StartDate DateTime
DECLARE @EndDate DateTime
set @StartDate = '2018-09-18 08:00:00.000'
set @EndDate = '2018-09-18 09:00:00.000'

SELECT a.Value as uiID, ISNULL(b.value, 0) as uiWater, cast(a.datetime as datetime2(0)) 
as dtCreated, 2 as Weightdata
FROM [INSQL].[Runtime].[dbo].[History] a
LEFT JOIN [INSQL].[Runtime].[dbo].[History] b ON a.datetime=b.datetime
WHERE a.TagName IN ('Weightdata2.uiID') and a.datetime>=@StartDate and 
a.datetime<=@EndDate and a.Value!=0
and ((b.TagName IN ('Weightdata2.uiWater') and b.datetime>=@StartDate and 
b.datetime<=@EndDate) OR b.datetime is null)
于 2018-09-29T13:47:03.740 回答
0

这更有可能是一份工作PIVOT：

;with cteData as (
    SELECT t.datetime, t.TagName, t.value
    FROM [INSQL].[Runtime].[dbo].[History] t
    WHERE t.datetime>=@StartDate and t.datetime<=@EndDate
    AND t.TagName IN ('Weightdata2.uiID', 'Weightdata2.uiWater')
)
SELECT 
  d.dtCreated,
  NULLIF(p.[Weightdata2.uiID], 0) as uiID,
  p.[Weightdata2.uiWater] as uiWater
FROM (
  SELECT 
    cast(d.datetime as datetime2(0)) as dtCreated,
    d.TagName, 
    d.value
  FROM cteData d
) d
PIVOT (
  MAX(d.value) for d.TagName in ([Weightdata2.uiID], [Weightdata2.uiWater])
) p

在所有情况下都会返回数据：当存在uiIDrow 但 nouiWater时，当两者都存在时，当 no uiIDbutuiWater存在时。

并且很容易调整为更长的标签列表。

于 2018-09-29T14:45:02.403 回答
0

可能只是这样：

with Perimeter as (
    SELECT t.datetime, t.TagName, t.value
    FROM [INSQL].[Runtime].[dbo].[History] t
    WHERE t.datetime between @StartDate and @EndDate
    AND t.TagName IN ('Weightdata2.uiID', 'Weightdata2.uiWater')
)
select f1.Value as uiID, ISNULL(f2.value, 0) as uiWater, 
cast(f1.datetime as datetime2(0)) as dtCreated, 2 as Weightdata
from Perimeter f1 
left outer join Perimeter f2 on f1.datetime=f2.datetime and f2.TagName='Weightdata2.uiWater'
where f1.TagName='Weightdata2.uiID'
于 2018-09-30T04:43:33.023 回答