oracle 查询语句where 后 and or 判断的灵活运用

select t.creator 建单人,
t.titles 工单主题,
t.statusdisplay 工单状态,
t.serialnumber 流水号
from up_itsm_iss t join v_depart_info rt on t.creatorid=rt.USERID
where
(('小计'='{3}' and t.iss_class like '%{4}%' )
or (rt.CNAME like '{3}' and t.iss_class like '%{4}%'))
and t.creator <> 'root' and (t.statusdisplay <> '已作废' or t.statusdisplay is null)