mqsql 排序并获取排序号，功能与oracle的rowrum函数类似.

示例如下：

方式一：

SELECT @rownum:=@rownum+1 rownum,t.* 
from (select @rownum:=0,c.* 
from rocky_account c order by id asc) t;

方式二：
SELECT @rank:=@rank+1 as rownum,a.* FROM (
SELECT * FROM rocky_account 
) a,(SELECT @rank:=0) b

方式三：
set @index=0;       
select @index:=(@index+1) as idx, a.* from rocky_account a;