select (@i:=@i+1) as i,table_name.* from table_name,(select @i:=0) as it
或者这个
set @rownum=0;select @rownum:=@rownum+1 as rownum, t.username from auth_user t limit 1,5;
SELECT @rowNum:=@rowNum + 1 AS '行号',a.* FROM 表名 a,(SELECT @rowNum:=0) b