If I'm correctly reading what you wrote, you're just looking for a way of creating your own category name for a selection of chassis types, right? If so, add the following CASE to your query:
CASE
WHEN TsysChassisTypes.ChassisName IN ('Desktop',
'Low Profile',
'Mini Tower',
'Tower',
'Space-Saving',
'All in One',
'Mini PC',
'Pizza Box',
'Sealed-Case') THEN 'Desktop'
WHEN TsysChassisTypes.ChassisName IN ('Portable',
'Laptop',
'Notebook',
'Convertible',
'Sub Notebook',
'Hand Held',
'Lunch Box') THEN 'Laptop'
ELSE 'Other'
END AS ChassisGroup,
and add the new field to your ORDERing.
I populated the CASE values from the contents of TsysChassisTypes. Unless you're certain that you don't have (or won't someday have) any of the other ChassisName values, you may want to consider expanding your WHERE filter.
Speaking of the WHERE clause, you can simplify it if you like:
Where
TsysChassisTypes.ChassisName IN ('Laptop', 'Notebook', 'Portable', 'Desktop')
As far as counting them,
Select Top 1000000
COUNT(*) AS [Count],
CASE
WHEN TsysChassisTypes.ChassisName IN ('Desktop',
'Low Profile',
'Mini Tower',
'Tower',
'Space-Saving',
'All in One',
'Mini PC',
'Pizza Box',
'Sealed-Case') THEN 'Desktop'
WHEN TsysChassisTypes.ChassisName IN ('Portable',
'Laptop',
'Notebook',
'Convertible',
'Sub Notebook',
'Hand Held',
'Lunch Box') THEN 'Laptop'
ELSE 'Other'
END AS [ChassisGroup]
From
tblAssetCustom
Inner Join tblAssets On tblAssetCustom.AssetID = tblAssets.AssetID
Inner Join tblSystemEnclosure On tblAssets.AssetID = tblSystemEnclosure.AssetID
Inner Join TsysChassisTypes On tblSystemEnclosure.ChassisTypes = TsysChassisTypes.Chassistype
Where
TsysChassisTypes.ChassisName IN ('Laptop', 'Notebook', 'Portable', 'Desktop')
Group By
CASE
WHEN TsysChassisTypes.ChassisName IN ('Desktop',
'Low Profile',
'Mini Tower',
'Tower',
'Space-Saving',
'All in One',
'Mini PC',
'Pizza Box',
'Sealed-Case') THEN 'Desktop'
WHEN TsysChassisTypes.ChassisName IN ('Portable',
'Laptop',
'Notebook',
'Convertible',
'Sub Notebook',
'Hand Held',
'Lunch Box') THEN 'Laptop'
ELSE 'Other'
END
should do the trick.