在表emp中 列出工资最小值小雨等于2000的职位
select job,min(sal)
from emp
where mina(sal)<=2000;为什么不对
为什么要写成
select job,min(sal)
from emp
group by job
having min(sal)<=2000;
group by 到底 有什么用
------解决方案--------------------
select 非聚合函数列，需要用group by
------解决方案--------------------
查看Group by的语法
Select [filed1,fild2,]聚合函数（filed）,
[Grouping(filed),]
[Grouping_id(filed1,filed2,…)]
From tablename
Where condition
[Group by {rollup
------解决方案--------------------
cube}(filed,filed2)]
[having condition]
[order by filed1]