>我有 2 列table_num,我的表中的 id 称为 medium
我想根据 DESC 的 id 序列回显没有重复table_num。
我通过此查询得到结果 4,2,7,5,3,但我想要的结果是 4,5,7,2,3
检查此图像的表结构
SELECT DISTINCT table_num FROM medium ORDER BY id DESC
你描述的顺序是升序,而不是降序:
SELECT DISTINCT table_num FROM medium ORDER BY id ASC
-- Here ------------------------------------------^
执行GROUP BY
,按每个table_num的最大 id 降序排序:
select table_num
from medium
group by table_num
order by max(id) desc
为了更好地了解它是如何工作的,请将max(id)
添加到选择列表中:
select table_num, max(id) as max_id
from medium
group by table_num
order by max_id desc