创建一个选择以“去标准化”＆＃39;表中的数据

Question

我把工作去标准化引号，因为它可能不是正确的方式，但不太确定如何描述它......

我有下表

Source   Priority   Attribute
A        1          Name
B        2          Name
C        3          Name
A        1          Address
B        2          Address
C        3          Address
A        2          Email
B        3          Email
C        1          Email

我希望我的选择返回：

Source Name_Pri  Addr_Pri  Email_Pri
A      1         1         2
B      2         2         3
C      3         3         1     

由于

Answer 1

您正在寻找一个支点。我经常使用条件聚合来做到这一点：

select source,
       max(case when attribute = 'Name' then priority end) as name_priority,
       max(case when attribute = 'Address' then priority end) as address_priority,
       max(case when attribute = 'Email' then priority end) as email_priority
from t
group by source;