SQL语句删除表中的字段只留下最新一行

方法一

DELETE FROM A WHERE `name` in (
SELECT a.name FROM(
SELECT name FROM A a GROUP BY name HAVING COUNT(`name`)>1
)a) AND id NOT IN( 
SELECT b.mid FROM
(SELECT MAX(`id`) AS mid FROM A b GROUP BY `name` HAVING COUNT(`name`)>1)b)
;

　　

方法二

DELETE FROM A WHERE id NOT in (
SELECT a.mid FROM (
SELECT MAX(id) as mid FROM A a GROUP BY name)a
);