This isn't a functioning query - it shows you what to SELECT, and the joins used - joined to tblassets
IsNull(scndtbl.Value, 'No Entry Found') As [WSUS Target Group],
IsNull(thrdtbl.Value, 'No Entry Found') As [WSUS Server]
Left Join (Select tblRegistry.AssetID,
tblRegistry.Valuename,
tblRegistry.Value,
tblRegistry.Regkey
From tblRegistry
Where tblRegistry.Valuename = 'TargetGroup' And
tblRegistry.Regkey Like '%SOFTWARE\Policies\Microsoft\Windows\WindowsUpdate') scndtbl
On tblAssets.AssetID = scndtbl.AssetID
Left Join (Select tblRegistry.AssetID,
tblRegistry.Valuename,
tblRegistry.Value,
tblRegistry.Regkey
From tblRegistry
Where tblRegistry.Valuename = 'WUServer' And
tblRegistry.Regkey Like '%SOFTWARE\Policies\Microsoft\Windows\WindowsUpdate') thrdtbl
On tblAssets.AssetID = thrdtbl.AssetID