Question

我查看了我已经提到的问题的版本，但是我发现的一些好的提示（例如，使用rank（）over（partition ...）似乎在我正在使用的Sybase版本中不起作用。

我希望运行一个按如下方式组织数据的过程：

电子邮件|偏好
  email1 | PreferenceXYZ
  email1 | PreferenceABC

并将其呈现在如下表格中：

电子邮件| Preference1 | Preference2
email1 | PreferenceXYZ | PreferenceABC

本质上，我有同一个人的多个记录（最好通过电子邮件记录识别为唯一标识符），我想为给定用户捕获这些多个首选项，并为每个用户创建1个单独记录（每封电子邮件）。 / p>

Answer 1

如果您只有两个偏好设置，那么您可以使用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：

如果您最多有七个值，请使用row_number()

进行转动

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II：

您实际上可以使用相关子查询而不是row_number()执行此操作：

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;

需要将具有相同ID的多行数据转换为具有多列的1行

1 个答案: