Question

我有五张桌子，我希望得到结果。这就是我在做什么：

select
        person.SERVICE_NO as Service_No, person.CNIC_NO as CNIC, person.NAME as NAME , card.CPLC_SERIAL_NO as Card_Number,
        child_dc.NAME as Child_DC, root_dc.NAME as Root_DC, person.OU as OU, person.EMAIL as Email
from
        person,card,person_card,child_dc,root_dc
where
        person_card.PERSON_ID = person.ID
and
        person_card.CARD_ID = card.ID
and
         person.CHILD_DC_ID = child_dc.ID
and
         root_dc.ID = child_dc.ID;

这个查询给出了冗余值，（如果我用它放置一个不同的值）。我当时正考虑用左手加入来做这件事;这意味着我将使用5张桌子进行LEFT OUTER JOINING。我该怎么做如果有人有更优化的查询或任何其他想法，那就太棒了。

Answer 1

查询已更新：

select  distinct
    person.SERVICE_NO as Service_No, 
    person.CNIC_NO as CNIC, person.NAME as NAME , 
    card.CPLC_SERIAL_NO as Card_Number,
    child_dc.NAME as Child_DC, 
    root_dc.NAME as Root_DC, person.OU as OU, 
    person.EMAIL as Email
from

     person_card inner join person
     on person_card.PERSON_ID = person.ID
     inner join card
     on person_card.CARD_ID = card.ID
        left outer join child_dc 
     on person.CHILD_DC_ID = child_dc.ID
        left outer join root_dc
    on child_dc.ID = root_dc.ID;

Oracle SQL查询（LEFT OUTER JOIN）

1 个答案: