Mysql 如何在sql中与3个表进行完全外部联接？

我有三张桌子：

表1：“vw_dimserver”：[ServerKey，ServerNm，ServerCurrentAssignedToNm]例如：[1234，hasgapp0108，Aya]

表2“vw_DimWorker”：[WorkerEmailNm，WorkerIdsid]。例如：[Aya，akhate]，[Genna，gshysh]，[mish，mishka]（就像名字和用户名一样）

表3“vw_FactHardwareAssetContact”：[ServerKey，HardwareAssetWorkerKey，HardwareAssetContactTypeNm]。例如：[1234，Aya，支持] [1234，Genna，客户] [1234，Mish，修补程序]（如果是支持、客户或修补程序，则为服务器密钥、联系人名称和联系人类型）

我需要输出在一行中： [ServerNm，ServerCurrentAssignedToNm的WorkerIdsid，客户的WorkerIdsid，支持的WorkerIdsid] [hasgapp0108，akhate，gshysh，mishka]

现在我需要与usernames表连接以获取每个用户的用户名。 我是用完全的外接做的

代码是：

挑选 vw_dimserver.ServerNm作为主机名， （vw_DimWorker1.WorkerIdsid）作为用户名， （vw_DimWorker2.WorkerIdsid）作为[主要支持联系人]， （vw_DimWorker3.WorkerIdsid）作为[主要客户联系人]

from vw_dimserver
        inner join vw_FactHardwareAssetContact  on vw_dimserver.ServerKey = vw_FactHardwareAssetContact.HardwareAssetKey 
    inner join vw_DimWorker as vw_DimWorker1  on  vw_DimWorker1.WorkerEmailNm = vw_dimserver.ServerCurrentAssignedToNm  
    full outer join  vw_DimWorker as  vw_DimWorker2 on   CONVERT(varchar(11),vw_FactHardwareAssetContact.HardwareAssetWorkerKey )  = vw_DimWorker2.workerWWID and vw_FactHardwareAssetContact.HardwareAssetContactTypeNm = 'Support' and vw_FactHardwareAssetContact.HardwareAssetPrimaryInd = '1'  and( vw_FactHardwareAssetContact.HardwareAssetWorkerKey is not NULL)
   full outer  join   vw_DimWorker as  vw_DimWorker3 on   CONVERT(varchar(11),vw_FactHardwareAssetContact.HardwareAssetWorkerKey )  = vw_DimWorker3.workerWWID and vw_FactHardwareAssetContact.HardwareAssetContactTypeNm = 'Customer' and vw_FactHardwareAssetContact.HardwareAssetPrimaryInd = '1' and( vw_FactHardwareAssetContact.HardwareAssetWorkerKey is not NULL)
where vw_dimserver.ServerNm ='hasgapp0108'   and (vw_DimWorker2.workerWWID is  not null or vw_DimWorker3.workerWWID is not null ) and ( ServerCurrentSubStatusCd != 'duplicate_error' or ServerCurrentSubStatusCd is NULL )

输出为两行：

[主机名用户名支持客户]

[hasgapp0108 akhate NULL gshysh]

[hasgapp0108 akhate akhate NULL]

我需要它是一排：

[主机名用户名支持客户]

[hasgapp0108 akhate akhate gshysh]

我的经理没有接受解决方案：

select max(username1),max(username2)...

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我需要使用连接来完成此操作。

尝试使用内部连接和组连接：

    SELECT vw_dimserver.ServerNm as hostname , group_concat(vw_DimWorker1.WorkerIdsid) as username, group_concat(vw_DimWorker2.WorkerIdsid) as [Primary Support Contact], group_concat(vw_DimWorker3.WorkerIdsid) as [Primary Customer Contact]

from vw_dimserver
        inner join vw_FactHardwareAssetContact  on vw_dimserver.ServerKey = vw_FactHardwareAssetContact.HardwareAssetKey 
    inner join vw_DimWorker as vw_DimWorker1  on  vw_DimWorker1.WorkerEmailNm = vw_dimserver.ServerCurrentAssignedToNm  
    full outer join  vw_DimWorker as  vw_DimWorker2 on   CONVERT(varchar(11),vw_FactHardwareAssetContact.HardwareAssetWorkerKey )  = vw_DimWorker2.workerWWID and vw_FactHardwareAssetContact.HardwareAssetContactTypeNm = 'Support' and vw_FactHardwareAssetContact.HardwareAssetPrimaryInd = '1'  and( vw_FactHardwareAssetContact.HardwareAssetWorkerKey is not NULL)
   full outer  join   vw_DimWorker as  vw_DimWorker3 on   CONVERT(varchar(11),vw_FactHardwareAssetContact.HardwareAssetWorkerKey )  = vw_DimWorker3.workerWWID and vw_FactHardwareAssetContact.HardwareAssetContactTypeNm = 'Customer' and vw_FactHardwareAssetContact.HardwareAssetPrimaryInd = '1' and( vw_FactHardwareAssetContact.HardwareAssetWorkerKey is not NULL)
where vw_dimserver.ServerNm ='hasgapp0108'   and (vw_DimWorker2.workerWWID is  not null or vw_DimWorker3.worker
group by vw_dimserver.ServerNm

---

如果只需要匹配结果，则可以使用内部联接

    SELECT
      s.ServerKey,
      s.ServerNm,
      group_concat(w.WorkerIdsid)
    FROM vw_dimserver s
    INNER JOIN vw_FactHardwareAssetContact c
      ON s.ServerKey = c.ServerKey
    INNER JOIN vw_DimWorker w
      ON c.HardwareAssetWorkerKey = w.WorkerEmailNm
    GROUP BY s.ServerKey,
             s.ServerNm

如果没有所有匹配项，也可以使用左连接

SELECT
  s.ServerKey,
  s.ServerNm,
  group_concat(w.WorkerIdsid)
FROM vw_dimserver s
LEFT JOIN vw_FactHardwareAssetContact c
  ON s.ServerKey = c.ServerKey
LEFT JOIN vw_DimWorker w
  ON c.HardwareAssetWorkerKey = w.WorkerEmailNm
GROUP BY s.ServerKey,
         s.ServerNm

---

选择vw_dimserver.ServerNm作为主机名，（vw_DimWorker1.WorkerIdsid）作为用户名，（vw_DimWorker2.WorkerIdsid）作为[主要支持联系人]，（vw_DimWorker3.WorkerIdsid）作为[主要客户联系人]

from vw_dimserver
        inner join vw_FactHardwareAssetContact  on vw_dimserver.ServerKey = vw_FactHardwareAssetContact.HardwareAssetKey 
    inner join vw_DimWorker as vw_DimWorker1  on  vw_DimWorker1.WorkerEmailNm = vw_dimserver.ServerCurrentAssignedToNm  
    full outer join  vw_DimWorker as  vw_DimWorker2 on   CONVERT(varchar(11),vw_FactHardwareAssetContact.HardwareAssetWorkerKey )  = vw_DimWorker2.workerWWID and vw_FactHardwareAssetContact.HardwareAssetContactTypeNm = 'Support' and vw_FactHardwareAssetContact.HardwareAssetPrimaryInd = '1'  and( vw_FactHardwareAssetContact.HardwareAssetWorkerKey is not NULL)
   full outer  join   vw_DimWorker as  vw_DimWorker3 on   CONVERT(varchar(11),vw_FactHardwareAssetContact.HardwareAssetWorkerKey )  = vw_DimWorker3.workerWWID and vw_FactHardwareAssetContact.HardwareAssetContactTypeNm = 'Customer' and vw_FactHardwareAssetContact.HardwareAssetPrimaryInd = '1' and( vw_FactHardwareAssetContact.HardwareAssetWorkerKey is not NULL)
where vw_dimserver.ServerNm ='hasgapp0108'   and (vw_DimWorker2.workerWWID is  not null or vw_DimWorker3.workerWWID is not null ) and ( ServerCurrentSubStatusCd != 'duplicate_error' or ServerCurrentSubStatusCd is NULL )

来自vw_dimserver

完全外部连接vw_FactHardwareAssetContact作为vw_FactHardwareAssetContact1 on（vw_dimserver.ServerKey=vw_FactHardwareAssetContact1.HardwareAssetKey和vw_FactHardwareAssetContact1.HardwareAssetContactTypeNm='Support'和vw_FactHardwareAssetContact1.HardwareAssetPrimaryId='1'）

转换时将vw_DimWorker作为vw_DimWorker1进行完全外部连接（varchar（11），vw_FactHardwareAssetContact1.HardwareAssetWorkerKey）=vw_DimWorker1.WorkerWid

完全外部连接vw_DimWorker作为assings上的assings.WorkerEmailNm=vw_dimserver.ServerCurrentAssignedToNm上的assings

完全外部连接vw_FactHardwareAssetContact作为vw_FactHardwareAssetContact2 on（vw_dimserver.ServerKey=vw_FactHardwareAssetContact2.HardwareAssetKey和vw_FactHardwareAssetContact2.HardwareAssetContactTypeNm='Customer'和vw_FactHardwareAssetContact2.HardwareAssetPrimaryId='1'）

转换时将vw_DimWorker作为vw_DimWorker2进行完全外部连接（varchar（11），vw_FactHardwareAssetContact2.HardwareAssetWorkerKey）=vw_DimWorker2.WorkerWid

完全外部连接vw_FactHardwareAssetContact作为vw_FactHardwareAssetContact11打开（vw_dimserver.ServerKey=vw_FactHardwareAssetContact11.HardwareAssetKey和vw_FactHardwareAssetContact11.HardwareAssetContactTypeNm='Support'和vw_FactHardwareAssetContact11.HardwareAssetPrimaryId='0'）

转换时将vw_DimWorker作为vw_DimWorker11进行完全外部连接（varchar（11），vw_FactHardwareAssetContact11.HardwareAssetWorkerKey）=vw_DimWorker11.WorkerWid

完全外部连接vw_FactHardwareAssetContact作为vw_FactHardwareAssetContact22 on（vw_dimserver.ServerKey=vw_FactHardwareAssetContact22.HardwareAssetKey和vw_FactHardwareAssetContact22.HardwareAssetContactTypeNm='Customer'和vw_FactHardwareAssetContact11.HardwareAssetPrimaryId='0'）

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完全外部连接vw_DimWorker作为vw_DimWorker22转换（varchar（11），vw_FactHardwareAssetContact22.HardwareAssetWorkerKey）=vw_DimWorker22.workerwid

在你的问题中，你只有2个表，而不是3.我编辑了我的帖子，请参见