Question

我有三个表：Account，Management和ManagementAccountLookup。

帐户表包含位置。 Management表包含业务层次结构中每个级别的记录。 Management表还包含一个值（ LevelID），它指示记录所在层次结构中的哪个级别.ManagementAccountLookup表是连接它们的查找表。

我在编写查询时遇到问题，无法通过两个相关的管理记录获取所有帐户。

例如：一个帐户可能有5个或更多与之关联的管理记录，但我只关心具有品牌或地区级别ID的两个特定管理。此外，我只希望帐户在结果网格中显示一次。

结果集应如下所示：

AccountID   Brand      Region
---------   --------   ------
account1    Wendys     East US
account2    McDonalds  West US

这似乎是一个简单的问题，但我无法弄清楚如何获得该结果。我已经尝试过自联接，子查询以及我能想到的其他所有内容，但我似乎无法将结果整合到一行中。

任何帮助都将不胜感激。

*编辑： ManagementAccountLookup有两个字段（AccountID，ManagementID）。这是其他两个表格的PK 管理层有一个LevelID列，可以告诉您该记录是品牌，地区，区等...

“品牌和区域”将是“管理”表格中的两个单独行。我需要结果网格将它们放在同一行。

Answer 1

您需要两次添加ManagementAccountLookup / Management组合以获取一行中的信息。我已将LevelID条件直接放入连接中，以便在需要时可以轻松转换为左连接。

select Account.AccountID,
       m_brand.Name Brand,
       m_region.Name Region
  from Account
 inner join ManagementAccountLookup mal_brand
    on Account.AccountID = mal_brand.AccountID
 inner join Management m_brand
    on mal_brand.ManagementID = m_brand.ManagementID
   and m_brand.LevelID = @Insert_Management_Brand_Level_Here
 inner join ManagementAccountLookup mal_region
    on Account.AccountID = mal_region.AccountID
 inner join Management m_region
    on mal_region.ManagementID = m_region.ManagementID
   and m_region.LevelID = @Insert_Management_Region_Level_Here

编辑：如果您需要显示所有帐户，可以在括号中使用左/内连接的组合：

select Account.AccountID,
       m_brand.Name Brand,
       m_region.Name Region
  from Account
  left join 
  (
       ManagementAccountLookup mal_brand
       inner join Management m_brand
         on mal_brand.ManagementID = m_brand.ManagementID
        and m_brand.LevelID = @Insert_Management_Brand_Level_Here
 )
   on Account.AccountID = mal_brand.AccountID
 left join 
 (
       ManagementAccountLookup mal_region
       inner join Management m_region
          on mal_region.ManagementID = m_region.ManagementID
         and m_region.LevelID = @Insert_Management_Region_Level_Here
 )
    on Account.AccountID = mal_region.AccountID

为了使其更具可读性，您可以使用CTE：

; with mal_level as (
  select AccountID,
         m.LevelID,
         m.Name
    from ManagementAccountLookup mal
   inner join Management m
      on mal.ManagementID = m.ManagementID
)
select Account.AccountID,
       m_brand.Name Brand,
       m_region.Name Region
  from Account
  left join mal_level m_brand
    on Account.AccountID = m_brand.AccountID
   and m_brand.LevelID = @Insert_Management_Brand_Level_Here
  left join mal_level m_region
    on Account.AccountID = m_region.AccountID
   and m_region.LevelID = @Insert_Management_Region_Level_Here

或outer apply：

select Account.AccountID,
       b.Brand,
       r.Region
  from Account
 outer apply
 (
       select m_brand.Name Brand
         from ManagementAccountLookup mal_brand
        inner join Management m_brand
           on mal_brand.ManagementID = m_brand.ManagementID
          and m_brand.LevelID = @Insert_Management_Brand_Level_Here
        where mal_brand.AccountID = Account.AccountID
 ) b
 outer apply
 (
       select m_region.Name Region
         from ManagementAccountLookup mal_region
        inner join Management m_region
           on mal_region.ManagementID = m_region.ManagementID
          and m_region.LevelID = @Insert_Management_Region_Level_Here
        where mal_region.AccountID = Account.AccountID
 ) r

多次加入表格

1 个答案: