如何將行值轉換爲列

Question

我有下表。讓我們叫它手機

-------------------------- 
| userid | type | number | 
-------------------------- 
| 1  | home | 123456 | 
-------------------------- 
| 1  |office| 654321 | 
-------------------------- 

，所以我希望它是這樣的：

-------------------------- 
| userid | home | office | 
-------------------------- 
| 1  |123456| 654321 | 
-------------------------- 

我試圖透視表，但問題是，我沒有任何領域聚集。任何建議？

PS 我使用Azure的SQL服務器

Answer 1

一種方法是：

with your_table(userid , type , number) as (
    select 1  ,'home','123456' union all 
    select 1  ,'office','654321' union all 
    select 2  ,'home','4444' union all 
    select 3  ,'office','77777' 
) 

-- below is actual query: 

select coalesce(t1.userid, t2.userid) as userid, t1.home, t2.office from 
(select userid, number as home from your_table where type = 'home') t1 
full join 
(select userid, number as office from your_table where type = 'office') t2 
on t1.userid = t2.userid 

如果您有其他價值觀也type列，並且您需要顯示他們爲列，那麼你應該加入另一個子查詢和full join也。

Answer 2

的情況下，您不必重複值：

select 
    user_id, 
    min(case when type='home' then type else null end) home, 
    min(case when type='office' then type else null end) office 
from 
    phone 
group by 
    userid;