simple update, I want to update max_seq with max(0rdr_seq) from another table.
how do you?

update h
set max_seq = d.max(ordr_seq)
from h_drug_stage_dup h
join drug_ordr_stage d
on h.patkey = d.patkey and
h.ordr_dtm= d.ordr_dtm and
h.h_drug = d.h_Drug