Question

我有两张桌子：

列有列的文件夹（folderid，foldername，userid）
列入列表的用户（folderid，shortlisteduserid）它们与folderid链接

我正在使用以下查询来获取由userid 50创建的文件夹列表，并计算50已将每个文件夹中的用户数列入候选

select a.folderid,a.foldername,count(b.ShortlistedUserId) as [count]
from tblshortlistfolders a left outer join tblshortlistedusers b on a.folderid=b.folderid 
where a.userid = 50
group by a.folderid,a.foldername

现在我想在此结果中再添加一列，其中每行的值将如下所示

如果folderid在tblshortlistedusers userid中包含49 值=＆＃39;是＆＃39;
如果folderid在tblshortlistedusers userid中不包含49 那么值=＆＃39;没有＆＃39;

但是当我以某种方式应用此条件时，列计数不会显示正确的值，并且结果不会按文件夹分组。多个行显示在同一文件夹的结果中。

如何获取所需的表格结果（folderid，foldername，totalcount，＆＃39; newcolumn＆＃39;）

Answer 1

如果您展示了您尝试过的查询，会有所帮助。我想这可能会做你想要的:(来自记忆）

select a.folderid,a.foldername,count(b.ShortlistedUserId) as [count]
,case when count(case when b.ShortlistedUserId=49 then 1 else null end)>0 then 'Yes' else 'No' end as [NewColumn]
from tblshortlistfolders a left outer join tblshortlistedusers b on a.folderid=b.folderid 
where a.userid = 50
group by a.folderid,a.foldername

修改也许我误解了你的数据。以下是一些包含一些示例数据的完整示例：

use tinker -- or whatever test db you have. CREATE TABLE tblshortlistfolders ( folderid INT NOT NULL primary key ,foldername NVARCHAR(255) ,userid INT NOT NULL ); CREATE TABLE tblshortlistedusers ( folderid INT NOT NULL ,shortlisteduserid INT NOT null ,constraint fk_tblshortlistedusers_folderid foreign key (folderid) references [dbo].[tblshortlistfolders] ); INSERT INTO tblshortlistfolders VALUES ( 100 , 'one' , 1); -- created by user 1 INSERT INTO tblshortlistfolders VALUES ( 200 , 'two' , 50); -- created by user 50 INSERT INTO tblshortlistfolders VALUES ( 300 , 'three' , 50); -- created by user 50 INSERT INTO tblshortlistfolders VALUES ( 400 , 'four' , 49); -- created by user 49 INSERT INTO tblshortlistedusers VALUES ( 100, 1); -- shortlisted by 50 INSERT INTO tblshortlistedusers VALUES ( 100, 50); -- shortlisted by 01 too INSERT INTO tblshortlistedusers VALUES ( 200, 50); -- shortlisted by 50 INSERT INTO tblshortlistedusers VALUES ( 200, 49); -- shortlisted by 49 too INSERT INTO tblshortlistedusers VALUES ( 300, 50); -- shortlisted by 50 INSERT INTO tblshortlistedusers VALUES ( 300, 50); -- shortlisted by 1 too SELECT a.folderid,a.foldername,COUNT(b.ShortlistedUserId) AS [COUNT] ,CASE WHEN COUNT(CASE WHEN b.ShortlistedUserId=49 THEN 1 ELSE NULL END)>0 THEN 'Yes' ELSE 'No' END AS [NewColumn] FROM tblshortlistfolders a LEFT OUTER JOIN tblshortlistedusers b ON a.folderid=b.folderid WHERE a.userid = 50 GROUP BY a.folderid,a.foldername

这就是我理解你的问题。也许你可以给出你想要的例子吗？

Answer 2

select 
    a.folderid,
    a.foldername,
    count(b.ShortlistedUserId) as [count],
    case when b.userid = 49 then 'yes' else 'no' end as [newcolumn]
from 
    tblshortlistfolders a 
    left outer join tblshortlistedusers b on a.folderid=b.folderid 
where a.userid = 50
group by a.folderid,a.foldername

尝试使用yes获取新列，没有值

2 个答案: