限制left join的右表方式

首先想到的方式直接限制

select 
    a.projectid
    ,DIM.projectname
    ,DIM.areaname
    ,to_char(a.msgtimestamp,'yyyyMMdd')
    --,count(a.id)
    ,count(1)              --客户询问数目
    ,count(b.id)           --24小时回复数目
from ods.xk_c_user_broker_chat_records a           --来询问人记录
inner join ods.xk_a_broker_user a1
on a.from_account=a1.id
left join ODS.XK_B_PROJECT DIM
ON A.projectid = DIM.id

left join ods.xk_c_user_broker_chat_records b 
    on a.conversationid=b.conversationid
    and b.msgtimestamp>=a.msgtimestamp
    and b.msgtimestamp<=a.msgtimestamp + INTERVAL '24' HOUR
    and b.DataType not IN ('system', 'timeoutMsg' )
    
-- inner join ods.xk_b_account c 
--         on c.id=b.to_account
--        and c.status=1 
--        and c.isdel=0
where a.projectid='01802085-5D65-4348-8088-550A4EFDC2EB'
and to_char(a.msgtimestamp,'yyyyMMdd')='20210831'
group by 
     a.projectid
    ,DIM.projectname
    ,DIM.areaname
    ,to_char(a.msgtimestamp,'yyyyMMdd')
order by to_char(a.msgtimestamp,'yyyyMMdd')

这段代码的想法是用C限制B表。但是实际上会把A也限制掉。因为A会先和B组成临时表然后C来限制这个临时表，C就对A有了限制作用

应该

with tmp as (
select
     a.projectid
    ,a.msgtimestamp msgtimestamp
    ,DIM.projectname
    ,DIM.areaname
    ,a.conversationid
    ,a.id
from ods.xk_c_user_broker_chat_records a           --来询问人记录
inner join ods.xk_a_broker_user a1
on a.from_account=a1.id
left join ODS.XK_B_PROJECT DIM
ON A.projectid = DIM.id
),
tmp1 as(
select
     b.conversationid
    ,b.id
    ,b.msgtimestamp msgtimestamp
from ods.xk_c_user_broker_chat_records b 
inner join ods.xk_b_account c 
        on c.id=b.to_account
       and c.status=1 
       and c.isdel=0
       and b.DataType not IN ('system','timeoutMsg')
where  b.projectid='01802085-5D65-4348-8088-550A4EFDC2EB'
and to_char(b.msgtimestamp,'yyyyMMdd') in ('20210831','20210901')
)

select 
     a.projectid
    ,a.projectname
    ,a.areaname
    ,to_char(a.msgtimestamp,'yyyyMMdd') msgtimestamp
    --,count(a.id)
    ,count(1)              --客户询问数目
    ,count(b.id)           --24小时回复数目
from  tmp a
left join(
select 
    bb.conversationid
    ,bb.id
    ,bb.msgtimestamp
from tmp aa
inner join tmp1 bb
on aa.conversationid=bb.conversationid
where bb.msgtimestamp>=aa.msgtimestamp
  and bb.msgtimestamp<=aa.msgtimestamp + INTERVAL '24' HOUR 
) b
on  a.conversationid=b.conversationid
where a.projectid='01802085-5D65-4348-8088-550A4EFDC2EB'
  and to_char(a.msgtimestamp,'yyyyMMdd')='20210831'
group by 
     a.projectid
    ,a.projectname
    ,a.areaname
    ,to_char(a.msgtimestamp,'yyyyMMdd')

限制left join的右表方式

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