需要将具有相同ID的多个行中的数据转换为具有多个列的1行

Question

我已回答了我的问题的已回顾版本，但是我发现了一些很好的提示（例如使用rank（）over（partition ...） ，似乎并没有在Sybase版本，我在上班

我希望能运行如下拉动组织数据的过程：

电子邮件|偏好
EMAIL1 | PreferenceXYZ
email1 | PreferenceABC

，呈现在一个表如下所示：

电子邮件|偏好1 | Preference2
email1 | PreferenceXYZ | PreferenceABC

从本质上说，我对同一个人（通过电子邮件记录最好确定为唯一标识符）的多条记录，我想捕捉到这些多喜好给定用户，并为每个用户创建1条个人记录（每电子邮件）。

Answer 1

如果你只有两个爱好，那么你可以使用min()和max()：

select email, min(preference) as preference1, 
     (case when min(preference) <> max(preference) then max(preference) end) as preference2 
from t 
group by email; 

编辑：

如果您有多达七个值，然后转动使用row_number()：

select email, 
     max(case when seqnum = 1 then preference end) as preference1, 
     max(case when seqnum = 2 then preference end) as preference2, 
     max(case when seqnum = 3 then preference end) as preference3, 
     max(case when seqnum = 4 then preference end) as preference4, 
     max(case when seqnum = 5 then preference end) as preference5, 
     max(case when seqnum = 6 then preference end) as preference6, 
     max(case when seqnum = 7 then preference end) as preference7 
from (select t.*, row_number() over (partition by email order by preference) as seqnum 
     from t 
    ) t 
group by email; 

编辑二：

你其实可以与相关子查询，而不是row_number()做到这一点：

select email, 
     max(case when seqnum = 1 then preference end) as preference1, 
     max(case when seqnum = 2 then preference end) as preference2, 
     max(case when seqnum = 3 then preference end) as preference3, 
     max(case when seqnum = 4 then preference end) as preference4, 
     max(case when seqnum = 5 then preference end) as preference5, 
     max(case when seqnum = 6 then preference end) as preference6, 
     max(case when seqnum = 7 then preference end) as preference7 
from (select t.*, 
      (select count(*) 
       from t t2 
       where t2.email = t.email and 
        t2.preference <= t.preference 
      ) as seqnum 
     from t 
    ) t 
group by email;