MySQL将一个字段中以逗号分隔的取出来形成新的字段

1例如：要把如图1的字段拆分图2

select  account_id,
        substring_index(substring_index(a.related_shop_ids,','
        ,b.help_topic_id+1),',',-1) shopid
    from 
        sales_hang_account a
    join
        mysql.help_topic b
        on b.help_topic_id < (length(a.related_shop_ids) -     length(replace(a.related_shop_ids,',',''))+1) 
   order by a.account_id

2：然后和shops表进行连接查询取出我们需要的字段，我这里需要取出name

select s.`name` as shopname,a.account_id from shops s
inner JOIN (

select  account_id,
        substring_index(substring_index(a.related_shop_ids,','
        ,b.help_topic_id+1),',',-1) shopid
    from 
        sales_hang_account a
    join
        mysql.help_topic b
        on b.help_topic_id < (length(a.related_shop_ids) -     length(replace(a.related_shop_ids,',',''))+1) 
   order by a.account_id)a on s.shop_id=a.shopid

3:将 account_id相同合并成一行，以逗号隔开

//这两个是网上的例子
select ID,group_concat(NAME) as NAME from table group by ID;

select ID,group_concat(NAME SEPARATOR ';') as NAME from a group by ID;
//借助上面两个参考
select account_id,GROUP_CONCAT(shopname SEPARATOR',')as shopname from (select s.`name` as shopname,a.account_id from shops s
inner JOIN (

select  account_id,
        substring_index(substring_index(a.related_shop_ids,','
        ,b.help_topic_id+1),',',-1) shopid
    from 
        sales_hang_account a
    join
        mysql.help_topic b
        on b.help_topic_id < (length(a.related_shop_ids) -     length(replace(a.related_shop_ids,',',''))+1) 
   order by a.account_id)a on s.shop_id=a.shopid) a GROUP BY account_id

效果如下