[英]SQL union / join / intersect multiple select statements
我有两个选择语句。 一个可以获取过去60秒内记录的电压数据列表(如果有)和相关的腔室名称,一个可以获取过去5分钟内记录的电弧事件数据的列表(如果有)。 我正在尝试将电弧计数数据作为新列追加到电压数据表中。 我不知道该怎么做。
请注意,对于电压数据表中给定的腔室名称,可能有也可能没有电弧计数行。 如果没有行,我想将圆弧计数列的值设置为零。
关于如何做到这一点的任何想法?
电压数据:
SELECT DISTINCT dbo.CoatingChambers.Name,
AVG(dbo.CoatingGridVoltage_Data.ChanA_DCVolts) AS ChanADC,
AVG(dbo.CoatingGridVoltage_Data.ChanB_DCVolts) AS ChanBDC,
AVG(dbo.CoatingGridVoltage_Data.ChanA_RFVolts) AS ChanARF,
AVG(dbo.CoatingGridVoltage_Data.ChanB_RFVolts) AS ChanBRF FROM
dbo.CoatingGridVoltage_Data LEFT OUTER JOIN dbo.CoatingChambers ON
dbo.CoatingGridVoltage_Data.CoatingChambersID =
dbo.CoatingChambers.CoatingChambersID WHERE
(dbo.CoatingGridVoltage_Data.DT > DATEADD(second, - 60,
SYSUTCDATETIME())) GROUP BY dbo.CoatingChambers.Name
退货
Name | ChanADC | ChanBDC | ChanARF | ChanBRF
-----+-------------------+--------------------+---------------------+------------------
OX2 | 2.9099999666214 | -0.485000004371007 | 0.344801843166351 | 0.49748428662618
S2 | 0.100000001490116 | -0.800000016887983 | 0.00690172302226226 | 0.700591623783112
S3 | 4.25666658083598 | 0.5 | 0.96554297208786 | 0.134956782062848
弧数表:
SELECT CoatingChambers.Name,
SUM(ArcCount) as ArcCount
FROM CoatingChambers
LEFT JOIN CoatingArc_Data
ON dbo.[CoatingArc_Data].CoatingChambersID = dbo.CoatingChambers.CoatingChambersID
where EventDT > DATEADD(mi,-5, GETDATE())
Group by Name
退货
Name | ArcCount
-----+---------
L1 | 283
L4 | 0
L6 | 1
S2 | 55
需要明确的是,鉴于上面的两个表,我想要这个表(添加了弧数列):
Name | ChanADC | ChanBDC | ChanARF | ChanBRF | ArcCount
-----+-------------------+--------------------+---------------------+-------------------+---------
OX2 | 2.9099999666214 | -0.485000004371007 | 0.344801843166351 | 0.49748428662618 | 0
S2 | 0.100000001490116 | -0.800000016887983 | 0.00690172302226226 | 0.700591623783112 | 55
S3 | 4.25666658083598 | 0.5 | 0.96554297208786 | 0.134956782062848 | 0
您可以将select语句视为虚拟表,然后将它们连接在一起:
select
x.Name,
x.ChanADC,
x.ChanBDC,
x.ChanARF,
x.ChanBRF,
isnull( y.ArcCount, 0 ) ArcCount
from
(
select distinct
cc.Name,
AVG(cgv.ChanA_DCVolts) AS ChanADC,
AVG(cgv.ChanB_DCVolts) AS ChanBDC,
AVG(cgv.ChanA_RFVolts) AS ChanARF,
AVG(cgv.ChanB_RFVolts) AS ChanBRF
from
dbo.CoatingGridVoltage_Data cgv
left outer join
dbo.CoatingChambers cc
on
cgv.CoatingChambersID = cc.CoatingChambersID
where
cgv.DT > dateadd(second, - 60, sysutcdatetime())
group by
cc.Name
) as x
left outer join
(
select
cc.Name,
sum(ac.ArcCount) as ArcCount
from
dbo.CoatingChambers cc
left outer join
dbo.CoatingArc_Data ac
on
ac.CoatingChambersID = cc.CoatingChambersID
where
EventDT > dateadd(mi,-5, getdate())
group by
Name
) as y
on
x.Name = y.Name
另外,用别名简化名称并格式化查询以提高可读性是值得的……我毫不客气地took了一下。
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