MySQL 8.0

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create table users( id integer primary key, name varchar(30) ) ;
insert into users( id, name ) values
(1, 'John'),(2, 'Michael'),(3, 'Someone') ;
create table orders( 
  id integer primary key
, userid integer
, content varchar(3) references users (id) 
);
insert into orders ( id, userid, content ) values
 (101, 1, '---'),(102, 1, '---')
,(103, 2, '---'),(104, 2, '---'),(105, 3, '---') ;
create or replace view userorders ( 
  userid, username, userdata 
)
as
select
  U.id, U.name, O.orders_
from ( 
  select 
    userid
  , group_concat( id order by id separator '|' )  as orders_
  from orders
  group by userid
) O join users U on O.userid = U.id ;
select * from userorders ;


userid
username
userdata


1
John
101|102

2
Michael
103|104

3
Someone
105


insert into orders ( id, userid, content ) values 
 (1000, 1, '***'),(4000, 1, '***'),(7000, 1, '***')
,(2000, 2, ':::'),(5000, 2, ':::'),(8000, 2, ':::')
,(3000, 3, '@@@'),(6000, 3, '@@@'),(9000, 3, '@@@') ;
select * from userorders ;


userid
username
userdata


1
John
101|102|1000|4000|7000

2
Michael
103|104|2000|5000|8000

3
Someone
105|3000|6000|9000

userid	username	userdata
1	John	101\|102\|1000\|4000\|7000
2	Michael	103\|104\|2000\|5000\|8000
3	Someone	105\|3000\|6000\|9000