MSSQL 动态透视列值到列标题 [英] MSSQL dynamic pivot column values to column header

问题描述

有人可以帮我在 mssql 上转换以下内容吗?

Could someone help me convert the following on mssql please?

 ID   |  PROPERTY_NAME  | PROPERTY_VALUE
 1    |      name1      |     value
 1    |      name2      |     value
 1    |      name3      |     value
 2    |      name4      |     value
 2    |      name2      |     value
 3    |      name6      |     value
..

PROPERTY_NAME &PROPERTY_VALUE 是标题，id 有多个属性"

PROPERTY_NAME & PROPERTY_VALUE being the headers, id having multiple 'properties'

我想把它转换成:

ID  |  NAME1  | NAME2  | NAME3  | NAME4  | NAME5  | NAME6  | nameETC...
1   |  value  | value  | value  |        |        |        | valueETC...
2   |         | value  |        | value  |        |        | valueETC...
3   |         |        |        |        |        | value  | valueETC...
..

在哪里 NAME1 |名称2 |NAME3 等现在是列标题.

Where NAME1 | NAME2 | NAME3 etc are now the column headers.

我猜是一个枢轴和一个从 MycoolTable 中选择不同的 PROPERTY_NAME"，但似乎无法将两者放在一起.

I'm guessing a pivot and a 'select distinct PROPERTY_NAME from MycoolTable' but can't seem to put the two together.

据我所知:(没有 server_id)列和所有地方的所有空值)显然我很愚蠢:D

This is as far as i got: (no server_id) column and all nulls everywhere) Clearly i'm stupid :D

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

select @cols = STUFF((SELECT distinct 
           ',' + QUOTENAME(PROPERTY_NAME)
               FROM [BSARA_DW_DB].[dbo].[SERVER_PROPERTY]
               FOR XML PATH(''), TYPE
               ).value('.', 'NVARCHAR(MAX)') 
               ,1,1,'');

SET @query = 'SELECT  '+ @cols + ' from 
         (
            SELECT SERVER_ID, PROPERTY_NAME, PROPERTY_CHAR_VAL
            FROM [BSARA_DW_DB].[dbo].[SERVER_PROPERTY]
        ) x
        pivot 
        (
            MAX(SERVER_ID)
            for PROPERTY_CHAR_VAL in (' + @cols + ')
        ) p ';

execute(@query)

非常感谢，迈克

推荐答案

您当前查询的问题在于:

The problem with your current query is with the line:

MAX(SERVER_ID)

您希望改为显示每个 PROPERTY_NAME 的 PROPERTY_CHAR_VAL.SERVER_ID 将作为列的最终结果的一部分.

You want to display the PROPERTY_CHAR_VAL for each PROPERTY_NAME instead. The SERVER_ID will be a part of the final result as a column.

有时当您使用 PIVOT 时，首先使用硬编码的值编写代码会更容易，类似于:

Sometimes when you are working with PIVOT is is easier to write the code first with the values hard-coded similar to:

select id, name1, name2, name3, name4
from
(
  select id, property_name, property_value
  from yourtable
) d
pivot
(
  max(property_value)
  for property_name in (name1, name2, name3, name4)
) piv;

请参阅 SQL Fiddle with Demo.

一旦你有了一个逻辑正确的版本，你就可以把它转换成动态 SQL 来得到结果.这将创建一个将被执行的 sql 字符串，它将包含您所有的新列名称.

Once you have a version that has the correct logic, then you can convert it to dynamic SQL to get the result. This will create a sql string that will be executed and it will include all of your new columns names.

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

select @cols = STUFF((SELECT distinct ',' + QUOTENAME(PROPERTY_NAME) 
                    from yourtable
            FOR XML PATH(''), TYPE
            ).value('.', 'NVARCHAR(MAX)') 
        ,1,1,'')

set @query = 'SELECT id, ' + @cols + ' 
            from 
            (
              select id, property_name, property_value
              from yourtable
            ) x
            pivot 
            (
                max(property_value)
                for property_name in (' + @cols + ')
            ) p '

execute sp_executesql @query;

参见 SQL Fiddle with Demo.两者都会给出结果:

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

| ID |  NAME1 |  NAME2 |  NAME3 |  NAME4 |  NAME6 |
|----|--------|--------|--------|--------|--------|
|  1 |  value |  value |  value | (null) | (null) |
|  2 | (null) |  value | (null) |  value | (null) |
|  3 | (null) | (null) | (null) | (null) |  value |

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