下列语句中，表T_AWT_PRD_PROD_OFFER_D_JQ存在重复记录，用rownum<2能正确选择重复的第一条么？
alter table T_MID_PRD_PROD_ITV_INST_jq add f_prod_offer_id number(8);
update T_MID_PRD_PROD_ITV_INST_jq a
set f_prod_offer_id =
(select prod_offer_id
from T_AWT_PRD_PROD_OFFER_D_JQ
where a.prod_inst_id_itv = instance_id
and prod_offer_id in ('30051351','30051338','30054150')
and rownum<2);
commit;