1.不按分组添加序号
1.第一种
select (@i := @i + 1) as rownum,b.* from table b, (SELECT @i := 0) as a order by region_id desc 2.第二种
set @i=0; select @i:=@i+1 as rownum, b.* from table b order by region_id desc 上面两种方法原理就是，事先定义一个变量，通过变量的递加以及虚拟表的联查达到生成序号列的目的
2.按分组添加序号
select -- rownum 判断 @now_region_id是否和当前的region_id一样,true:让 @i+=1 false:重置@i (@i := case when @now_region_id=region_id then @i + 1 else 1 end ) rownum, -- 设置 @now_region_id等于region_id (@now_region_id:=region_id), b.*, from table b, (SELECT @i := 0, @now_region_id:=') as a order by region_id desc———————————————— 版权
