I moved your forum topic to the report requests section.
You can reach your goal by using a subquery which lists computers having "domain admins" in their local administrator group and excluding these assets from your main report. Please find an example below.
Select Top 1000000 tblAssets.AssetID,
tblAssets.AssetName,
tsysOS.Image As icon,
tblAssets.Lastseen,
tblAssets.Lasttried
From tblAssets
Inner Join tblAssetCustom On tblAssets.AssetID = tblAssetCustom.AssetID
Left Join tsysOS On tblAssets.OScode = tsysOS.OScode
Where tblAssetCustom.State = 1 And tblAssetCustom.AssetID Not In (Select
tblUsersInGroup.AssetID From tblUsersInGroup
Where tblUsersInGroup.Username Like 'domain admins' And
tblUsersInGroup.Admingroup = 1) And tblAssets.Assettype = -1
Order By tblAssets.AssetName