mysql：查询当前数据的所在行号

select  @rownum:=@rownum+1 rownum, sys_organ.* from (select @rownum:=0) r, sys_organ order by sys_id desc;

 

更新某一字段等于所在行号：

set @num = 0;

update sys_organ set organ_num = (@num := @num + 1);