ผมต้องการเรียง ว/ด/ป Field "day_ordain(varchar)" จากก่อนไปหาหลัง(ล่าสุด)

Select * from (select *, right(or_date,4) y, substring(or_date,4,2) m, left(or_date,2) d from tbname ) tb order by y, m, d

$sql_select_mem="Select * from (select *, right(day_ordain,4) y, substring(day_ordain,4,2) m, left(day_ordain,2) d from member ) member where wantstudy_name = 'ปธ.1-2' order by y, m, d limit $goto,$pagesize";