两列的不同值

Question

这是我用来获取不同值的查询：

SELECT DISTINCT
    LOGIN_BY,
    RECEIVED_BY
FROM SAMPLE

我的要求是我需要将两列的不同值作为单个输出。有没有办法做到这一点？

Answer 1

试试这个

(SELECT DISTINCT LOGIN_BY as ID from sample )
union all
(Select Distinct RECEIVED_BY as ID FROM SAMPLE)

Answer 2

试试这样：

select distinct a from (
  select
    distinct LOGIN_BY as a
  from
    SAMPLE
  union
  select
    distinct RECEIVED_BY as a
  from
    SAMPLE
);

这适用于Oracle数据库。