ไม่รู้แบบนี้จะถูกไหมครับ
select l.hn,p.pname,p.fname,p.lname from lab_head l
left outer join patient p on p.hn = l.hn
left outer join lab_order o on l.lab_order_number = o.lab_order_number
where l.order_date between '2010-10-01' and '2011-10-31' and o.lab_items_code = "185" and l.hn in (select hn from clinicmember where clinic = 001 )
group by l.hn
having count(o.lab_items_code = "185") > 1