sql server合并多个数据集不重复数据

Question

给定三个表 Ta、Tb、Tc:

Ta(ID, Field1)
Tb(ID, Field2)
Tc(ID, Field3)

给定数据示例:

Ta
ID Field1
---------
1  A
1  B

Tb
ID Field2
---------
1  C
1  D
2  E

Tc
ID Field3
---------
1  F
2  G
2  H

问题: 我如何加入此数据以返回:

ID Field1 Field2 Field3
-----------------------
1  A      C      F
1  B      D      NULL
2  NULL   E      G
2  NULL   NULL   H

我以为我可以通过外连接实现这一点，但事实似乎并非如此。分组的顺序并不重要，只要我带回所有没有重复行的信息即可。

澄清一下。我真的不介意得到哪种组合，只要结果集以最少的行数返回所有数据即可。这是我正在尝试做的一个更现实的例子:

给定一个人，称他为约翰。他有两个电话号码和三个电子邮件地址:

PID  Email
---------
John john@test.com
John john@mail.com
John john@john.com

PID  Tel
--------
John 011
John 022

我要返回:

PID  Email         Tel
----------------------
John john@test.com 011
John john@mail.com 022
John john@john.com NULL

Answer 1

您可以通过以下方式接近:

select coalesce(ta.id, tb.id, tc.id), ta.field1, tb.field2, tc.field3
from (select ta.*, row_number() over (partition by id order by (select NULL)) as seqnum
      from ta
     ) ta full outer join
     (select tb.*, row_number() over (partition by id order by (select NULL)) as seqnum
      from tb
     ) tb
     on ta.id = tb.id and
        ta.seqnum = tb.seqnum
     (select tc.*, row_number() over (partition by id order by (select NULL)) as seqnum
      from tc
     ) tc
     on coalesce(ta.id, tb.id) = tc.id and
        coalesce(ta.seqnum, tb.seqnum) = tc.seqnum
group by coalesce(ta.id, tb.id, tc.id),
         coalesce(ta.seqnum, tb.seqnum, tc.seqnum)
order by 1, 2

不过正如我所说，在我的评论中，无法保证表中行的顺序，因此这些行可能不会按照您期望的顺序出现。使用示例数据，您可以使用:

over (partition by id order by field<n>)

如果字段定义顺序