sql - 基于单列返回唯一行

Question

我有一张桌子（员工）。

员工

ID   Name   Salary  Department
------------------------------
1    Steve  10000   SQ
2    Buck   15000   AS
3    Dan    10000   SQ
4    Dave   10000   AS
5    Jack   30000   AS
6    Amy    8000    GM

我需要每个部门返回一名员工。例如，对于上述日期，我需要返回如下数据：

ID   Name   Salary  Department
------------------------------
1    Steve  10000   SQ   ( I can either return Steve or Dan for this group SQ)
2    Buck   15000   AS   ( I can either return Buck or Dave or Jack for this group AS)
6    Amy    8000    GM

Answer 1

这是一个很好的用途row_number()：

select id, name, salary, department
from (select t.*,
             row_number() over (partition by department order by department) as seqnum
      from t
     ) t
where seqnum = 1

如果您想要第一个或最后一个 id，请在分区子句中使用order by id asc或。如果您想要一个随机行，请使用.order by id descrow_number()order by dbms_random.value