转置行和列而无聚集 [英] Transpose rows and columns with no aggregate

问题描述

我有以下数据集

Account Contact

1   324324324
1   674323234
2   833343432
2   433243443
3   787655455
4   754327545
4   455435435
5   543544355
5   432455553
5   432433242
5   432432432

我希望输出如下:

Account Contact1    Contact2    Contact3    Contact4

1   324324324   674323234       
2   833343432   433243443       
3   787655455           
4   754327545   455435435       
5   543544355   432455553   432433242   432432432

问题还在于我的帐户和帐户数量未定未确定的联系人数量

The problem is also that I have an unfixed amount of Accounts & unfixed amount of Contacts

推荐答案

如果要应用PIVOT函数，则将需要使用聚合函数来获取结果，但同时还希望使用窗口化像row_number()这样的功能，可以为帐户中的每个联系人生成唯一的序列.

If you are going to apply the PIVOT function, you will need to use an aggregate function to get the result but you will also want to use a windowing function like row_number() to generate a unique sequence for each contact in the account.

首先，您将查询类似于以下内容的数据:

First, you will query your data similar to:

select account, contact,
  'contact'
    + cast(row_number() over(partition by account
                              order by contact) as varchar(10)) seq
from yourtable

请参见带演示的SQL Fiddle .这将创建一个具有唯一序列的新列:

See SQL Fiddle with Demo. This will create a new column with the unique sequence:

| ACCOUNT |   CONTACT |      SEQ |
|---------|-----------|----------|
|       1 | 324324324 | contact1 |
|       1 | 674323234 | contact2 |

如果列数有限，则可以对查询进行硬编码:

If you have a limited number of columns, then you could hard-code your query:

select account,
  contact1, contact2, contact3, contact4
from 
(
  select account, contact,
    'contact'
      + cast(row_number() over(partition by account
                                order by contact) as varchar(10)) seq
  from yourtable
) d
pivot
(
  max(contact)
  for seq in (contact1, contact2, contact3, contact4)
) piv;

请参见带演示的SQL小提琴

如果列数未知，则必须使用动态SQL:

If you have an unknown number of columns, then you will have to use dynamic SQL:

DECLARE @cols AS NVARCHAR(MAX),
    @query  AS NVARCHAR(MAX)

select @cols = STUFF((SELECT ',' + QUOTENAME(seq) 
                    from
                    (
                      select 'contact'
                              + cast(row_number() over(partition by account
                                                        order by contact) as varchar(10)) seq
                      from yourtable
                    ) d
                    group by seq
                    order by seq
            FOR XML PATH(''), TYPE
            ).value('.', 'NVARCHAR(MAX)') 
        ,1,1,'')

set @query = 'SELECT account, ' + @cols + ' 
            from 
            (
                select account, contact,
                  ''contact''
                    + cast(row_number() over(partition by account
                                              order by contact) as varchar(10)) seq
                from yourtable
            ) x
            pivot 
            (
                max(contact)
                for seq in (' + @cols + ')
            ) p '

execute sp_executesql @query;

请参见带演示的SQL小提琴.两者都会给您带来以下结果:

See SQL Fiddle with Demo. Both will give you a result of:

| ACCOUNT |  CONTACT1 |  CONTACT2 |  CONTACT3 |  CONTACT4 |
|---------|-----------|-----------|-----------|-----------|
|       1 | 324324324 | 674323234 |    (null) |    (null) |
|       2 | 433243443 | 833343432 |    (null) |    (null) |
|       3 | 787655455 |    (null) |    (null) |    (null) |
|       4 | 455435435 | 754327545 |    (null) |    (null) |
|       5 | 432432432 | 432433242 | 432455553 | 543544355 |

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