1、求最大值,注意图中红线标出的语句select 测点编号, 测值 as 最大值, 时间 from 测值表 wh髫潋啜缅ere ID not in (select a.ID from 测值表 a,测值表 b where a.测值<b.测值 and a.测点编号=b.测点编号);select 测点编号,测值 as 最大值,时间from 测值表where ID not in(select a.ID from 测值表 ainner join 测值表 b on a.测点编号=b.测点编号where a.测值<b.测值);
2、求最小值,注意图中红线标出的语句select 测点编号, 测值 as 最小值, 时间 from 测值表 wh髫潋啜缅ere ID not in (select a.ID from 测值表 a,测值表 b where a.测值>b.测值 and a.测点编号=b.测点编号); select 测点编号, 测值 as 最小值, 时间 from 测值表 where ID not in (select a.ID from 测值表 a inner join 测值表 b on a.测点编号=b.测点编号 where a.测值>b.测值);