Question

我在创建数据透视查询方面遇到了一些问题：

我有这些数据：

DECLARE @UserAccess TABLE
(
    userName char(255),
    project char(255),
    role char(255)
);

userName  project  role
--------  -------  ----
ado       BI       U
aga       BI       D
aga       BI       U
mim       BI       A
mim       BI       U
ado       BID      D
ado       BID      U
aga       BID      D
aga       BID      U
mim       BID      A
mim       BID      D
mim       BID      U

我想要的是：

User    BI    BID
-----   ---   ---
ado     U     DU
aga     DU    DU
mim     AU    ADU

但我无法弄清楚如何构建语句来获得这个。

Answer 1

首先，您需要将roles连接成一行，然后才能应用PIVOT函数：

select username, BI, BID
from
(
  select username, project, 
    STUFF((SELECT distinct '' + t.[role]
         from UserAccess t
         where u.username = t.username
           and u.project = t.project
            FOR XML PATH(''), TYPE
            ).value('.', 'NVARCHAR(MAX)') 
        ,1,0,'') role
  from UserAccess u
) d
pivot
(
  max(role)
  for project in (BI, BID)
) piv;

见SQL Fiddle with Demo。

这也可以使用带有CASE表达式的聚合函数编写：

;with cte as
(
  select username, project, 
    STUFF((SELECT distinct '' + t.[role]
         from UserAccess t
         where u.username = t.username
           and u.project = t.project
            FOR XML PATH(''), TYPE
            ).value('.', 'NVARCHAR(MAX)') 
        ,1,0,'') role
  from UserAccess u
)
select username,
  max(case when project = 'BI' then role end) BI,
  max(case when project = 'BID' then role end) BID
from cte
group by username;

请参阅SQL Fiddle with Demo

如何在T-SQL中定义Pivot语句？

1 个答案: