select
    deb.id
  , mc.cid
  , mc.mail_month
 from fte_intra.debiteuren deb
left join gmsms.mail_count mc on (mc.cid = deb.id)
where
      deb.type='sms'
  AND (deb.Afloop_contract='0000-00-00' OR month(deb.Afloop_contract)='$lastmonth')
  AND mc.month='$lastmonth'
  AND mc.year='$yearG'
group by deb.id
order by deb.id