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分别担任CU、ITPUB以及CSDN社区的MySQL版主! 我本来想说我是吃屎的! ^_^
  yueliangdao0608.cublog.cn

关于作者
姓名:杨涛
职业:DBA
年龄:25
位置:中国-武汉市
个性介绍:又长了一岁
QQ:38257291
MSN:yueliangdao0608@gmail.com
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我的分类


[原创]关于分组序号在MySQL中的实现
好像ORACLE中有相应的函数,可惜在MSSQL 或者MySQL中没有对应的函数。后两者就得用临时表来实现了。

1、表结构以及示例数据。

create table company
(dep char(10) not null,
val1 int unsigned not null
);
insert into company values
(
'市场部', 26),
('市场部',25),
('市场部',24),
('办公室',16),
('办公室',12),
('研发部',19),
('研发部'
,11);

2、存储过程

1)、循环实现

DELIMITER $$

CREATE DEFINER=`root`@`%` PROCEDURE `sp_generate_auto`()
BEGIN
declare cnt int default 0;
declare i int default 0;
drop table if exists tmp;
-- Temporary table to save the result.
create temporary table tmp like company;
alter table tmp add num int unsigned not null;
select count(1) as total from (select count(1) from company where 1 group by dep) T into cnt;
while i < cnt
do
set @stmt = concat('select dep from company where 1 group by dep order by dep asc limit ',i,',1 into @t_dep');
prepare s1 from @stmt;
execute s1;
deallocate prepare s1;
set @stmt = NULL;
set @num = 0;
set @stmt2 = concat('insert into tmp select dep,val1,@num := @num + 1 as sequence from company where dep = ''',@t_dep,''' order by dep asc');
prepare s1 from @stmt2;
execute s1;
deallocate prepare s1;
set @stmt2 = NULL;
set i = i + 1;
end while;
select * from tmp;
set @t_dep = NULL;
END$$

DELIMITER ;

2)、游标实现

DELIMITER $$



DROP PROCEDURE IF EXISTS `sp_generate_auto_cursor`$$



CREATE DEFINER=`root`@`%` PROCEDURE `sp_generate_auto_cursor`()

BEGIN

  declare done1 int default 0;

  declare a char(10);

  declare i int unsigned default 0;
-- Cursor one to get the group total
  declare cur1 cursor for select dep from company group by dep;

  declare continue handler for 1329 set done1 = 1;

-- Temporary table to save the result.

  drop table if exists tmp;

  create table tmp like company;

  alter table tmp add num int unsigned not null;

  open cur1;

  while done1 != 1

  do

    fetch cur1 into a;

    if not done1 then

      set @i = 0;

      begin

      declare done2 int default 0;

      declare b int unsigned default 0;

      declare c int unsigned default 0;
-- Cursor two to get per group total.
      declare cur2 cursor for select val1,@i := @i + 1 from company where dep = a;

      declare continue handler for 1329 set done2 = 1;

        open cur2;

        while done2 <> 1

        do

          fetch cur2 into b,c;

          if not done2 then

            insert into tmp select a,b,c;

          end if;

        end while;

        close cur2;

      end;

    end if;

  end while;

  close cur1;

  select * from tmp;

END$$



DELIMITER ;



3、调用结果

call sp_generate_auto();
call sp_generate_auto_cursor();

query result(7 records)

depval1num
办公室 16 1
办公室 12 2
市场部 26 1
市场部 25 2
市场部 24 3
研发部 19 1
研发部 11 2

uery result(7 records)

depval1num
办公室 16 1
办公室 12 2
市场部 26 1
市场部 25 2
市场部 24 3
研发部 19 1
研发部 11 2
(7 row(s)returned)
(15 ms taken)

(0 row(s)affected)
(0 ms taken)

(7 row(s)returned)
(16 ms taken)

(0 row(s)affected)
(0 ms taken)





发表于: 2008-07-02,修改于: 2008-07-02 13:45,已浏览546次,有评论1条 推荐 投诉


网友评论
网友: fredyj 时间:2008-08-19 11:04:08 IP地址:123.127.164.★
似乎不用临时表 

set @num = 0;
set @dep = '';
select *,
@num := if(@dep = dep, @num + 1, 1) as row_number,
@dep := dep as dummy
from company
order by dep;

ZT: http://www.xaprb.com/blog/2006/12/02/how-to-number-rows-in-mysql/

Blog作者的回复:
这样也可以!


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