经典SQL语句

1、以某字段为分组，也就是说此字段不重复 select * from ArpInfo group by id 2、计算总量 select sum(Counts) from ArpInfo where id=400 3、跨表查询按某组数量排序的信息 select member.*,sum(record.count) as aa from member, record where member.id=record.id group by member.id order by aa desc 4、to do...