MySQL query parameters in a table field - mysql

Question

Good afternoon.
I have two tables:
1 - table1 - (id, address, who_lives) who_lives field - text, comma-separated list of identifiers
2 - table2 - (id, name_of_resident)
composition of table 1
12| US Oregon | 12,13
14| US Washington| 9,11
composition of table 2
9 |Petrov
11|Sidorov
12|Ivanov
13|Popov
How to make MySQL request, preferably via join, that the result was
US Oregon |Ivanov,Popov
US Washington|Petrov,Sidorov
If possible, replace the comma with the br tag: Ivanov,Popov -> Ivanov >br< Popov

Answer 1

SELECT table1.address, GROUP_CONCAT(table2.name_of_resident SEPARATOR '<br>')
FROM table1
JOIN table2 ON FIND_IN_SET(table2.id, table1.who_lives)
GROUP BY table1.address
DEMO

Answer 2

That is not how you design tables. Don't do comma separated listes. Do either a (foreign) key from table 2 to table 1, or a table with table1.id and table2.id for each relation.
Then writing the query will be easier.
create table state (
state_id int primary key,
address varchar(255)
);
create table resident (
resident_id int primary key,
name varchar(255)
);
create table who_lives (
state_id int,
resident_id int,
primary key (state_id, resident_id)
);
insert into state values (12, 'US Oregon');
insert into state values (14, 'US Washington');
insert into resident values (9, 'Petrov');
insert into resident values (11, 'Sidorov');
insert into resident values (12, 'Ivanov');
insert into resident values (13, 'Popov');
insert into who_lives values (12, 12);
insert into who_lives values (12, 13);
insert into who_lives values (14, 9);
insert into who_lives values (14, 11);
select address, group_concat(name)
from state
join who_lives using (state_id)
join resident using (resident_id)
group by state_id;
http://sqlfiddle.com/#!9/e7041f/2