SQL 将行转换为列 [英] SQL Convert Rows To Columns

问题描述

我知道这已经被问过几次了，但我找不到任何适合我的例子的解决方案.

I know this has been asked a few times before, but I can't find any solution that fits my example.

我目前拥有使用某些页面的用户权限表.表格如下所示:

I currently have a table of user permissions to use certain pages. The table would look like this:

UserID    pagename         pageid
-----------------------------------
1         home             1
1         contacts         3
3         home             1
2         links            2

如何从这些数据中生成一个表格，其中所有页面名称都以列的形式列出，表格的每一行都用于一个用户 ID，列值根据原始表格是否有显示为 0 或 1该特定页面的条目，例如:

How would I generate a table from this data where I have all the page names tabulated as columns and each row of the table is for a User ID, the column values display 0 or 1 based on whether or not the original table had an entry for that particular page, for instance:

UserID     home     links    contacts
-------------------------------------
1          1        0        1
2          0        1        0
3          1        0        0

非常感谢您的帮助！

推荐答案

在@t 中构建你的表:

Build your table in @t:

declare @t as table (UserID int, pagename nvarchar(20), pageid int);
insert into @t values (1,'home',1),(1,'contacts',3),(3,'home',1),(2,'links',2);

旋转它:

select UserID, 
    case when home is null then 0 else 1 end as home, 
    case when links is null then 0 else 1 end as links, 
    case when contacts is null then 0 else 1 end as contacts
from @t
pivot (
    max(pageid) for pagename in ([home],[links],[contacts])
) pivotT

UserID      home        links       contacts
----------- ----------- ----------- -----------
1           1           0           1
2           0           1           0
3           1           0           0

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