是否将多条记录合并为一个人拥有的一条记录

Question

如何打开以下内容：

username | userLastFirst    | email             | approver1         |department
FAlbert  | Albert, Frankie  | [e-mail]  | Doe, John         |HR
FAlbert  | Albert, Frankie  | [e-mail]  | Smith, Mike       |HR

进入：

username | userLastFirst    | email             | approver1    |approver2   |department
FAlbert  | Albert, Frankie  | [e-mail]  | Doe, John    |Smith, Mike |HR

我希望将同一用户的多行及其审批人合并为一个记录，其中包含审批人的列。

Answer 1

如果有两行，可以使用聚合：

select username, userLastFirst, email, min(approver) as approver1 ,
nullif(max(approver), min(approver)) as approver2, department
from t
group by username, userLastFirst, email, department;