select * from a where a.zd3 = (select max(zd3) from a b where a.zd1=b.zd1)
SELECT * FROM a WHERE NOT EXISTS (SELECT * FROM a b WHERE b.zd1 = a.zd1 AND b.zd3 > a.zd3);
select * from b d where not exists(select 1 from b where zd1=d.zd1 and d.ZD3<ZD3)order by d.ZD3
select (select a2.id from a a2 where a2.zd1 = a1.zd1 and a2.zd3 = (select max(a3.zd3) from a a3 where a3.zd1 = a1.zd1)) as id, a1.zd1, (select a2.zd3 from a a2 where a2.zd1 = a1.zd1 and a2.zd3 = (select max(a3.zd3) from a a3 where a3.zd1 = a1.zd1)) as zd3 from a a1 group by a1.zd1 order by a1.zd1
FROM a
WHERE NOT EXISTS (SELECT *
FROM a b
WHERE b.zd1 = a.zd1
AND b.zd3 > a.zd3);
from a a2
where a2.zd1 = a1.zd1
and a2.zd3 = (select max(a3.zd3) from a a3 where a3.zd1 = a1.zd1)) as id,
a1.zd1,
(select a2.zd3
from a a2
where a2.zd1 = a1.zd1
and a2.zd3 = (select max(a3.zd3) from a a3 where a3.zd1 = a1.zd1)) as zd3
from a a1
group by a1.zd1
order by a1.zd1
2楼的可以 比我的好 学习了