SQL union/join/intersect多个select语句

Question

我有两个select语句。在过去的60秒内获得记录的电压数据的列表（如果有的话）和相关的房间名称，并且在过去的5分钟内获得记录的电弧事件数据的列表（如果有的话）。我试图将电弧计数数据作为新列附加到电压数据表中。我无法弄清楚如何做到这一点。

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，我想将弧计数列值设置为零。

有关如何完成此任何想法？

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 

返回

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 

弧伯爵表：

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 

返回

Name | ArcCount 
-----+--------- 
L1 | 283 
L4 |  0 
L6 |  1 
S2 | 55 

要清楚，我想这个表（添加弧数列），鉴于上面的两个表：

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 

Answer 1

你可以把在SELECT语句作为虚拟表，只是它们连接起来：

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，值得用别名来简化你的名字，并将查询格式化为可读性......我无耻地进行了刺探。