count(distinct 订单号）和count(*)as 订单数`````group by 订单号,这两个语句是不是

count(distinct 订单号）和count(*)as 订单数`````group by 订单号,这两个语句是不是 group by zuozhebianhao having count(*)>=3 group by 和 distinct 的问题 SQL语句中的 Distinct 和 Group by 有什么不同,用那个好? group by 零件号 having count（项目号）=3 group by o.ownerid having count(o.id)>=2 oracle中 HAVING count(1) group by sex having count(*)>4; 怎么使用 select telnum,count(0),count(distinct othertelnum) from nmk. count,count和count的区别 count select count(*) as total from 'test' order by id desc 这样的SQL select语句怎么写?怎么显示数据 distinct,order by,group by,having?