SQL 表行到列 - 可能的 PIVOT？

Question

我有一个来自 Active Direcory 的信息表，但不幸的是它是这样显示的；

+------+------------+----------------+-------------------+
| dnId | propNameId |  propertyName  |   propertyValue   |
+------+------------+----------------+-------------------+
|    1 |         10 | objectsid      | S-1-5-32-548      |
|    1 |         19 | _objectclass   | group             |
|    1 |         80 | cn             | Account Operators |
|    1 |         82 | samaccountname | Account Operators |
|    1 |         85 | name           | Account Operators |
|    2 |         10 | objectsid      | S-1-5-32-544      |
|    2 |         19 | _objectclass   | group             |
|    2 |         80 | cn             | Administrators    |
|    2 |         82 | samaccountname | Administrators    |
|    2 |         85 | name           | Administrators    |
|    3 |         10 | objectsid      | S-1-5-32-551      |
|    3 |         19 | _objectclass   | group             |
|    3 |         80 | cn             | Backup Operators  |
|    3 |         82 | samaccountname | Backup Operators  |
|    3 |         85 | name           | Backup Operators  |
+------+------------+----------------+-------------------+

使用一堆临时表和连接，我可以让它显示我想要的方式，就像这样；

+------+--------------+--------------+-------------------+-------------------+-------------------+
| dnId |  objectsid   | _objectclass |        cn         |  samaccountname   |       name        |
+------+--------------+--------------+-------------------+-------------------+-------------------+
|    1 | S-1-5-32-548 | group        | Account Operators | Account Operators | Account Operators |
|    2 | S-1-5-32-544 | group        | Administrators    | Administrators    | Administrators    |
|    3 | S-1-5-32-551 | group        | Backup Operators  | Backup Operators  | Backup Operators  |
+------+--------------+--------------+-------------------+-------------------+-------------------+

但这感觉真的很混乱和冗长.. 我确信一定有更优雅的方式来做到这一点，也许使用 PIVOT，我已经尝试过（但失败了）明白。

有什么想法/建议吗？

编辑：抱歉，删除了 mysql 标签（这是自动建议的）。我正在使用 MS SQL Server 2008 R2。

Answer 1

您没有指定您使用的数据库，但以下将在 SQL Server 或 MySQL 中工作。您可以使用带有 CASE 表达式的聚合函数来创建新的列名：

select
  dnid,
  max(case when propertyName = 'objectsid' then propertyValue end) objectsid,
  max(case when propertyName = '_objectclass ' then propertyValue end) objectclass ,
  max(case when propertyName = 'cn' then propertyValue end) cn,
  max(case when propertyName = 'samaccountname' then propertyValue end) samaccountname,
max(case when propertyName = 'name' then propertyValue end) name
from yourtable
group by dnid;

见SQL Fiddle with Demo

Answer 2

如果您使用的是 SQL Server（从您的标签中不确定），此查询将生成您正在寻找的结果，使用 PIVOT

SELECT p.*
FROM (
  SELECT dnId, propertyName, propertyValue FROM myTable
) AS t
PIVOT(
  MAX(propertyValue)
  FOR propertyName IN (objectsid, _objectclass, cn, samaccountname, name)
) AS p;

查看SQL Fiddle here