需要將具有相同ID的多個行中的數據轉換爲具有多個列的1行

Question

我已回答了我的問題的已回顧版本，但是我發現了一些很好的提示（例如使用rank（）over（partition ...） ，似乎並沒有在Sybase版本，我在上班

我希望能運行如下拉動組織數據的過程：

電子郵件|偏好
EMAIL1 | PreferenceXYZ
email1 | PreferenceABC

，呈現在一個表如下所示：

電子郵件|偏好1 | Preference2
email1 | PreferenceXYZ | PreferenceABC

從本質上說，我對同一個人（通過電子郵件記錄最好確定爲唯一標識符）的多條記錄，我想捕捉到這些多喜好給定用戶，併爲每個用戶創建1條個人記錄（每電子郵件）。

Answer 1

如果你只有兩個愛好，那麼你可以使用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; 

編輯：

如果您有多達七個值，然後轉動使用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; 

編輯二：

你其實可以與相關子查詢，而不是row_number()做到這一點：

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;