MySQL takes out the comma-separated values ​​from a field to form a new field

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

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 

//These two are examples from the Internet 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;
//With the help of the above two references 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

select g.account_id,g.related_shop_ids,GROUP_CONCAT(s.name)as shopname from sales_hang_account g left join shops s on FIND_IN_SET(s.shop_id , g.related_shop_ids)
GROUP BY g.account_id 

 [Product] -- The storage format of this field is 7,8,9,11,10,12, and the data type is nvarchar
select id,ProductName=stuff((select ',' + product_chinaname from base_supplier_product where charindex(','+ltrim(productid)+',',','+ Product + ',') > 0 for xml path('') ), 1, 1, '')
 FROM base_Pre_sale_project