SQL Group by on outer reference after 2 inner joins - sql

Question

My sql query is not working as intended, in its current form it will return results, but some of them on the second column are duplicated, or in other words, some the computer names followed by the drive letter show twice.
The query is this:
(select Distinct 'ServerDrive' as storageType, cast(assetname as
varchar)+ '\ ' +cast(caption as varchar) as storagePath,((rqDiskdrivesHist.
[size]-rqDiskdrivesHist.[freespace])/1024/1024) as usedMB,(rqDiskdrivesHist.
[size]/1024/1024) as sizeMB from lansweeperdb.dbo.tblAssets
inner join rqDiskdrivesHist
on lansweeperdb.dbo.tblAssets.AssetID=rqDiskdrivesHist.AssetID
where drivetype=3
and lansweeperdb.dbo.tblAssets.AssetName in
(select distinct entitypath from rqcentities
inner join rqcustomer
on rqcentities.customerID=rqcustomer.customerID
where customername like '%ak 26%' and entityType='computer'
and not (
(AssetName like 'WFP3675' and caption like 'D:')
or
(AssetName like 'WFP3675' and caption like 'E:')
or
(AssetName like 'WFP3675' and caption like 'F:')
or
(AssetName like '%00500%')
)
))
If I try to group by at the end. with:
GROUP BY cast(assetname as varchar)+'\'+cast(caption as varchar)
I will get the "Each GROUP BY expression must contain at least one column that is not an outer reference.
" error.
Edit: These are 2 rows from the results which are duplicated.

Answer 1

You need to group on the alias instead as you did not expose those fields in the inner query.
SELECT
storageType,
storagePath,
MaxMB = MAX(usedMB),
MinMB = MIN(usedMB),
AvgMB = AVG(usedMB)
FROM
(
select 'ServerDrive' as storageType,
cast(assetname as varchar)+ '\ ' +cast(caption as varchar) as storagePath,
((rqDiskdrivesHist.[size]-rqDiskdrivesHist.[freespace])/1024/1024) as usedMB,
(rqDiskdrivesHist.[size]/1024/1024) as sizeMB
from
lansweeperdb.dbo.tblAssets
inner join rqDiskdrivesHist on lansweeperdb.dbo.tblAssets.AssetID=rqDiskdrivesHist.AssetID
where
drivetype=3
and lansweeperdb.dbo.tblAssets.AssetName in
(
select distinct entitypath
from rqcentities
inner join rqcustomer on rqcentities.customerID=rqcustomer.customerID
where customername like '%ak 26%' and entityType='computer'
and not (
(AssetName like 'WFP3675' and caption like 'D:')
or
(AssetName like 'WFP3675' and caption like 'E:')
or
(AssetName like 'WFP3675' and caption like 'F:')
or
(AssetName like '%00500%')
)
)
) AS X
GROUP BY
storagePath,
storageType