• 方法1：

select a.* from tb a 
where val = (select max(val) from tb where name = a.name) 
order by a.name

或者(这种可以控制取第几条，如最大第一条，第二条，第三条最后一条等等)

select a.* from tb a 
where val = (select val from tb where name = a.name order by val limit 0,1) 
order by a.name

• 方法2：

select a.* from tb a 
where not exists
(select 1 from tb where name = a.name and val > a.val)

• 方法3：

select a.* from tb a,
(select name,max(val) val from tb group by name) b 
where 
a.name = b.name 
and a.val = b.val 
order by a.name

• 方法4：

select a.* 
from tb a inner join 
(select name , max(val) val from tb group by name) b 
on a.name = b.name and a.val = b.val 
order by a.name

• 方法5

select a.* from tb a 
where 
1 > (select count(*) from tb where name = a.name and val > a.val )
 order by a.name

注意：子查询中的结果类型，作为条件匹配主语句，会有索引失效导致长时间匹配问题，不同可类型转换成一致，如方法一=匹配（这里是一致的），不一致请转化,其他类似。
如方法一：

select a.* from tb a 
where val = (select max(CAST(val AS SIGNED)) as val from tb where name = a.name) 
order by a.name