Mysql 技巧 —— 分组后每条记录取最新

Posted 2020-12-16 lemos

方法1

左连接

SELECT m1.*
FROM messages m1 LEFT JOIN messages m2
 ON (m1.name = m2.name AND m1.id < m2.id)
WHERE m2.id IS NULL;

 子查询

select * from messages where id in
(select max(id) from messages group by Name)

 mysql8 窗口函数

WITH ranked_messages AS (
  SELECT m.*, ROW_NUMBER() OVER (PARTITION BY name ORDER BY id DESC) AS rn
  FROM messages AS m
)
SELECT * FROM ranked_messages WHERE rn = 1;

 

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