Here are two checks using joins, one with sqlite, one with the join builtin of ksh93:

  check_empty_vhosts () {
    # Check which vhost adapter doesn't have any VTD mapped
    start_sqlite
    tosql "SELECT l.vios_name,l.vadapter_name FROM vios_vadapter AS l
        LEFT OUTER JOIN vios_wwn_disk_vadapter_vtd AS r
    USING (vadapter_name,vios_name)
    WHERE r.vadapter_name IS NULL AND
      r.vios_name IS NULL AND
   l.vadapter_name LIKE 'vhost%';"
    endsql
    getsql
    stop_sqlite
  }

  check_empty_vhosts_sh () {
    # same as above, but on the shell
    join  -v 1  -t , -1 1 -2 1 \
   <(while IFS=, read vio host slot; do 
  if [[ $host == vhost* ]]; then
      print ${vio}_$host,$slot 
  fi
     done < $VIO_ADAPTER_SLOT | sort -t , -k 1)\
   <(while IFS=, read vio vhost vtd disk; do
  if [[ $vhost == vhost* ]]; then        
    print ${vio}_$vhost
  fi
     done < $VIO_VHOST_VTD_DISK | sort -t , -k 1)
  }