How can I display one Mysql row to multiple rows? - mysql

Question

I need some help please.
I have this simple mysql query:
select '1,2,3,4,5,6' as Col1 from dual;
and the table1:
Col1
1,2,3,4,5,6
And I have another table2:
service_id service_name
1 Service1
2 Service2
I tried next query but not working:
select service_name from table2 where service_id in (select col1 from table1)
Any help would be appreciated!

Answer 1

Try this:
Sample data:
create table `dual` (Col1 varchar(100));
insert into `dual` values ('1,2,3,4,5,6');
create table table2 (service_id int, service_name varchar(100));
insert into table2 values
(1, 'Service1'),
(2, 'Service2');
T-SQL:
select service_name from table2 t2
where exists(
select 1 from `dual` d
where locate(concat(',', t2.service_id, ','), concat(',', d.Col1, ',')) > 0
);

Answer 2

I'm not sure exactly what you're trying to accomplish, but I can give you a couple hints.
Your "IN" clause would only work if your service_id was '1,2,3,4,5,6'. I can see what you're trying to do, but the database is treating the result from col1 as the whole string of numbers including all the commas, not the individual numbers themselves. If you hard-coded it as "WHERE IN (1,2,3,4,5,6)", you would be getting matches. Instead of using the "IN" clause, you could JOIN the tables and use LIKE.
Try This:
SELECT
table2.service_name
FROM
table2
LEFT OUTER JOIN
table1
ON
table1.col1 LIKE CONCAT('%', table2.service_id, '%')
WHERE
table1.col1 IS NOT NULL
I think that will do what I think you want to do.