简单的MYSQL独立选择

Question

如果我有一个包含两列的表，名称和时间戳以及一堆将具有共享名称的行。如何选择共享相同名称的每组行中的最新行？

谢谢！

Answer 1

SELECT name, MAX(timestamp) FROM Table1 GROUP BY name 

编辑：根据评论，请尝试以下方法：

SELECT name, timestamp, col3, col4 
FROM Table1 t1 
WHERE timestamp = (SELECT MAX(t2.timestamp) 
       FROM Table1 t2 
       WHERE t1.name = t2.name); 

---

添加人MCHL没有相关子查询

版（应该有更好的表现）

SELECT 
    t1.name, t1.timestamp, t1.col3, t1.col4 
FROM 
    Table1 AS t1 
CROSS JOIN (
    SELECT 
    name, MAX(timestamp) AS timestamp 
    FROM 
    Table1 
    GROUP BY 
    name 
) AS sq 
USING (name,timestamp) 

Answer 2

然后你需要一个子查询：

SELECT columns 
FROM Table1 t1 
WHERE row_id = (SELECT row_id 
       FROM table1 t2 
       WHERE t1.name = t2.name 
       ORDER BY timestamp DESC 
       LIMIT 1) 
GROUP BY name 

编辑，忘了按名称