复杂SQL学习

select * from (select d.*,  rownum r from (select a.req_id req_id,a.imcc_order_id imcc_order_id,

to_char(a.input_date,'yyyy-MM-dd') input_date,

a.title title, a.approve_dept approve_dept, a.approve_advice approve_advice,

to_char(a.approve_time,'yyyy-MM-dd') approve_time,

to_char(a.resolve_time,'yyyy-MM-dd') resolve_time,

to_char(a.out_time,'yyyy-MM-dd') out_time,a.outFlag outFlag,

(select org_name from o_org where org_no= b.org_no) req_orgNo,

b.severity severity,

b.second_category second_category,

b.event_original event_original,

c.system_name system_name 

from WEB_REQUIREMENT a left join work_order b

on a.imcc_order_id = b.imcc_order_id 

left join SER_SYSTEM_INFO c 

on b.app_sys = c.system_info_id

where a.resolve_time is null and a.input_date is not null 

order by input_date desc) d)  where r > 1 and r < 2