SQL union / join / intersect multiple select statements - sql

Question

I have two select statements. One gets a list (if any) of logged voltage data in the past 60 seconds and related chamber names, and one gets a list (if any) of logged arc event data in the past 5 minutes. I am trying to append the arc count data as new columns to the voltage data table. I cannot figure out how to do this.
Note that, there may or may not be arc count rows, for a given chamber name that is in the voltage data table. If there are no rows, I want to set the arc count column value to zero.
Any ideas on how to accomplish this?
Voltage Data:
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
Returns
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
Arc count table:
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
Returns
Name | ArcCount
-----+---------
L1 | 283
L4 | 0
L6 | 1
S2 | 55
To be clear, I want this table (with added arc count column), given the two tables above:
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

You can treat the select statements as virtual tables and just join them together:
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
Also, it's worthwhile to simplify your names with aliases and format the queries for readability...which I shamelessly took a stab at.