Mysql数据库多对多关系未建新表

-- 新建user表
CREATE TABLE `user` (
    `id` INT(11) NOT NULL COMMENT ‘人员id‘,
    `uname` VARCHAR(50) NULL DEFAULT NULL COMMENT ‘人员姓名‘,
    `hobbies` VARCHAR(255) NULL DEFAULT NULL COMMENT ‘业余爱好id(以逗号分割)‘,
    PRIMARY KEY (`id`)
)
COLLATE=‘utf8_general_ci‘
ENGINE=InnoDB;
-- 新建业余爱好表
CREATE TABLE `hobby` (
    `id` INT(12) NOT NULL AUTO_INCREMENT COMMENT ‘爱好id‘,
    `name` VARCHAR(255) NULL DEFAULT NULL COMMENT ‘爱好名称‘,
    PRIMARY KEY (`id`)
)
COLLATE=‘utf8_general_ci‘
ENGINE=InnoDB
AUTO_INCREMENT=0;

SELECT
    u.*,
    group_concat( h.`name` ) AS hbs 
FROM
    USER u
    LEFT JOIN hobby h ON FIND_IN_SET( h.id, u.hobbies ) 
GROUP BY
    u.id

SELECT u.* FROM user u WHERE FIND_IN_SET(#{hid},u.hobbies);

select u.*,substring_index(substring_index(u.hobbies,‘,‘,b.help_topic_id+1),‘,‘,-1) hob
from user u join
  mysql.help_topic b
    on b.help_topic_id < (length(u.hobbies) - length(replace(u.hobbies, ‘,‘, ‘‘)) + 1)
order by u.id;