oracle中单字段存在1个或2个关联id时的查询sql

//上午值班人数为1人或2人时，查出值班信息和个人信息
select 
b.contact as mContact,b.email as mEmail,
c.contact as m2Contact,c.email as m2Email,
t.* from(
select
substr(a.morning_people_ids,0,instr(a.morning_people_ids,',',1,1)-1) as amId,
substr(a.morning_people_ids,instr(a.morning_people_ids,',',1,1)+1) as bmId,
a.*
from tb_duty a 
) t,
tb_duty_person_info b,
tb_duty_person_info c
where 1=1 and
nvl2(t.amId,t.amId,t.bmId)=b.person_id 
and t.bmId=c.person_id 
and t.dscd='340100' and t.unit_id=4 
and t.day0='2015-08-06'

//整个8月的
select 
m1.person_name as mName,
m1.contact as mContact,m1.email as mEmail,
m2.person_name as m2Name,
m2.contact as m2Contact,m2.email as m2Email,
a1.person_name as aName,
a1.contact as aContact,a1.email as aEmail,
a2.person_name as a2Name,
a2.contact as a2Contact,a2.email as a2Email,
e1.person_name as eName,
e1.contact as eContact,e1.email as eEmail,
e2.person_name as e2Name,
e2.contact as e2Contact,e2.email as e2Email,
l1.person_name as lName,
l1.contact as lContact,l1.email as lEmail,
l2.person_name as l2Name,
l2.contact as l2Contact,l2.email as l2Email,
t.week_day,
t.flag,
t.day0
 from(
select
substr(a.morning_people_ids,0,instr(a.morning_people_ids,',',1,1)-1) as mId,
substr(a.morning_people_ids,instr(a.morning_people_ids,',',1,1)+1) as m2Id,

substr(a.afternoon_people_ids,0,instr(a.afternoon_people_ids,',',1,1)-1) as aId,
substr(a.afternoon_people_ids,instr(a.afternoon_people_ids,',',1,1)+1) as a2Id,

substr(a.evening_people_ids,0,instr(a.evening_people_ids,',',1,1)-1) as eId,
substr(a.evening_people_ids,instr(a.evening_people_ids,',',1,1)+1) as e2Id,

substr(a.leader_ids,0,instr(a.leader_ids,',',1,1)-1) as lId,
substr(a.leader_ids,instr(a.leader_ids,',',1,1)+1) as l2Id,

a.*
from tb_duty a 
) t,
tb_duty_person_info m1,
tb_duty_person_info m2,
tb_duty_person_info a1,
tb_duty_person_info a2,
tb_duty_person_info e1,
tb_duty_person_info e2,
tb_duty_person_info l1,
tb_duty_person_info l2
where 1=1 
and
nvl2(t.mId,t.mId,t.m2Id)=m1.person_id 
and t.m2Id=m2.person_id 
and
nvl2(t.aId,t.aId,t.a2Id)=a1.person_id 
and t.a2Id=a2.person_id 
and
nvl2(t.eId,t.eId,t.e2Id)=e1.person_id 
and t.e2Id=e2.person_id 
and
nvl2(t.lId,t.lId,t.l2Id)=l1.person_id 
and t.l2Id=l2.person_id 
and t.dscd='340100' and t.unit_id=4 
and to_char(to_date(t.day0,'yyyy-mm-dd'),'yyyy-mm')='2015-08'

附：

//查询tb_duty_person_info第11-20条记录（根据person_id排序）：
   //0.031秒
   select a.* from (
   select rownum rn ,b.* from tb_duty_person_info b  where rownum<21 order by b.person_id
   ) a 
   where a.rn>10;
   //0.047秒
      select a.* from (
   select rownum rn ,b.* from tb_duty_person_info b order by b.person_id
   ) a 
   where a.rn>10 and rn<21 ;