mysql中把一字段拆分成列模式

pro_game_info表中type字段值如下：
gtype='即时制,角色扮演,模拟,网络,休闲,解谜,动作,策略'
gtype='即时制,角色扮演,模拟'

需求把gtype值按照','拆分成多列模式值，即


模拟
网络
休闲
解谜
动作
策略
动作
财务

方法如下：
CREATE DEFINER=`gtcom`@`%` PROCEDURE `pro_game_type`()
begin
DECLARE type int(6);
DECLARE i int DEFAULT 0;
-- 查询最大','的数量
select max(length(gtype)-length(replace(gtype,',',''))) into type from pro_game_info;

-- 创建辅助表
CREATE TABLE if not exists help_game_type ( id INT(11),PRIMARY KEY (`id`));
truncate table help_game_type;
while i <type+1 do
insert into help_game_type (id) values (i);
set i =i+1;
end while;
-- 插入足够的辅助数据
while i < type+1 do
insert into help_game_type(id) values (i); set i=i+1;
end while;

-- 统计结果展示
TRUNCATE table help_game_tmp;
INSERT into help_game_tmp(gtype,n)
select gtype,count(*) n from
(SELECT substring_index(substring_index(t.gtype,',',b.id + 1),',',- 1) as gtype
FROM pro_game_info t JOIN help_game_type b ON b.id<(LENGTH(t.gtype) - LENGTH(REPLACE(t.gtype, ',', '')) + 1) and t.gtype<>''
) as t
group by gtype ORDER BY n desc;
end