Question

如何使用左连接语法将其与两个选择查询相结合。（我的查询有错误，我找不到解决方案）

select
    *
from
    (select
        mi.parent_entity_id entity,
        tctp.institution_rec_id institutionRecId,
        institution_code storecode,
        institution_name storename,
        case when sum(unsettled_points) is null
            then coalesce (sum(point_value),0)
            else coalesce
        (sum(unsettled_points),0) end sumpoints
     from
        t_card_transaction_point tctp
     inner join
        m_institution mi on tctp.institution_rec_id=mi.institution_rec_id
     where
        mi.parent_entity_id = 70125 and
        tctp.point_status = 'xy4604'
     group by
        entity,
        institutionRecId,
        storecode,
        storename
    ) storeExpired

left join
    entityExpired on storeExpired.entity=entityExpired.entity

(select
    mpb.institution_rec_id entity,
    tctd.institution_rec_id institutionRecId,
    tctd.card_no cardnumber,
    total_amount_primary totalpoints,
    case when total_unsettled_points is null
        then point_value
        else tctd.total_unsettled_points end
    points
 from
    t_card_transaction_detail tctd inner
 join
    m_point_bucket mpb on mpb.card_no=tctd.card_no
 inner join
    m_institution mi on mi.institution_rec_id=tctd.institution_rec_id
 where
    mpb.total_amount_primary > 1000 and
    tctd.adjustment_date is null
 group by
    entity,
    institutionRecId,
    cardnumber,
    totalpoints,
    points
) entityExpired

Answer 1

首先：我们非常感谢代码的正确缩进/衬里以便于阅读：）

第二： “我的查询有错误”并没有特别说明。

Anywho，回答你的问题：

SQL具有

的操作顺序

从
其中
分组依据
具有
选择
按订单排序

这意味着在执行select时会创建别名。由于“分组依据”在此之前执行，因此别名不存在 - 这可能是您得到的错误。

另外，我不确定MySQL是否允许连接别名，这在查询中进一步定义（虽然我可能是错的），所以我会将查询本身移动到连接括号中，并使用在“开启” - 后来的声明。

示例查询:(未经测试，因为我没有表格）

select 
* 
from (
   select 
     mi.parent_entity_id      as entity
   , tctp.institution_rec_id  as institutionRecId
   , institution_code         as storecode
   , institution_name         as storename
   , case when sum(unsettled_points) is null 
      then coalesce (sum(point_value),0) 
      else coalesce (sum(unsettled_points),0) 
   end                        as sumpoints 
   from t_card_transaction_point tctp 
   inner join m_institution      mi on tctp.institution_rec_id = mi.institution_rec_id 
   where 1=1
   and mi.parent_entity_id = 70125 
   and tctp.point_status = 'xy4604' 
   group by 
     mi.parent_entity_id
   , tctp.institution_rec_id
   , institution_code
   , institution_name
) storeExpired
left join (
   select 
     mpb.institution_rec_id   as entity
   , tctd.institution_rec_id  as institutionRecId
   , tctd.card_no             as cardnumber
   , total_amount_primary     as totalpoints
   , case when total_unsettled_points is null 
      then point_value 
      else tctd.total_unsettled_points 
   end                        as points 
   from t_card_transaction_detail tctd 
   inner join m_point_bucket      mpb  on mpb.card_no=tctd.card_no 
   inner join m_institution       mi   on mi.institution_rec_id=tctd.institution_rec_id 
   where 1=1
   and mpb.total_amount_primary > 1000 
   and tctd.adjustment_date is null 
   group by 
     mpb.institution_rec_id
   , tctd.institution_rec_id
   , tctd.card_no
   , total_amount_primary
   , case when total_unsettled_points is null 
      then point_value 
      else tctd.total_unsettled_points 
   end
) entityExpired on storeExpired.entity=entityExpired.entity

修改我只是谷歌了，你实际上可以在你的群组中使用别名的MySQL语句（在MSSQL中不允许，也不是ANSI标准）。

但是，在看到您对错误的评论后，可能是因为您在创建子查询之前加入别名entityExpired。我猜测移动子查询，就像我在示例中所做的那样，应该可以工作。

使用LEFT OUTER JOIN组合2个SELECT查询

1 个答案: