Block SCCM Clients - lookup SQL table

#Requires -Modules ConfigurationManager
# Needs Configuration Manager Cmdlets from  . . .
# https://technet.microsoft.com/en-us/library/dn958404%28v=sc.20%29.aspx

$list = Invoke-Sqlcmd -Query "SELECT host FROM BUILD.DBO.SCCMBLOCK;" -ServerInstance "MYSQLSVR"
$collectionname = 'Blocked Clients'

Set-Location IRL:
foreach($c in $list.host) {

   try {
      Add-CMDeviceCollectionDirectMembershipRule -CollectionName $collectionname -ResourceId $(get-cmdevice -Name $c).ResourceID
      "Moved $c to Blocked Clients Collection"
       }
   catch {
      "Invalid client or direct membership rule may already exist: $c"
       }

   try {
      Block-CMDevice -DeviceName $c 
      "Blocked $c"
       }

    catch {
      "Failed to block: $c"
       }
}

$list = Invoke-Sqlcmd -Query "delete FROM BUILD.DBO.SCCMBLOCK;" -ServerInstance "MYSQLSVR"