First of all consider to store the data in a normalized way. Here is a good read: Is storing a delimited list in a database column really that bad?
Now - Assumng the following schema and data:
create table products (
id int auto_increment,
upc varchar(50),
upc_variation text,
primary key (id),
index (upc)
);
insert into products (upc, upc_variation) values
('01234', '01234,12345,23456'),
('56789', '45678,34567'),
('056789', '045678,034567');
We want to find products with variations '12345' and '34567'. The expected result is the 1st and the 2nd rows.
Normalized schema - many-to-many relation
Instead of storing the values in a comma separated list, create a new table, which maps product IDs with variations:
create table products_upc_variations (
product_id int,
upc_variation varchar(50),
primary key (product_id, upc_variation),
index (upc_variation, product_id)
);
insert into products_upc_variations (product_id, upc_variation) values
(1, '01234'),
(1, '12345'),
(1, '23456'),
(2, '45678'),
(2, '34567'),
(3, '045678'),
(3, '034567');
The select query would be:
select distinct p.*
from products p
join products_upc_variations v on v.product_id = p.id
where v.upc_variation in ('12345', '34567');
As you see - With a normalized schema the problem can be solved with a quite basic query. And we can effectively use indices.
"Exploiting" a FULLTEXT INDEX
With a FULLTEXT INDEX on (upc_variation) you can use:
select p.*
from products p
where match (upc_variation) against ('12345 34567');
This looks quite "pretty" and is probably efficient. But though it works for this example, I wouldn't feel comfortable with this solution, because I can't say exactly, when it doesn't work.
Using JSON_OVERLAPS()
Since MySQL 8.0.17 you can use JSON_OVERLAPS(). You should either store the values as a JSON array, or convert the list to JSON "on the fly":
select p.*
from products p
where json_overlaps(
'["12345","34567"]',
concat('["', replace(upc_variation, ',', '","'), '"]')
);
No index can be used for this. But neither can for FIND_IN_SET().
Using JSON_TABLE()
Since MySQL 8.0.4 you can use JSON_TABLE() to generate a normalized representation of the data "on the fly". Here again you would either store the data in a JSON array, or convert the list to JSON in the query:
select distinct p.*
from products p
join json_table(
concat('["', replace(p.upc_variation, ',', '","'), '"]'),
'$[*]' columns (upcv text path '$')
) v
where v.upcv in ('12345', '34567');
No index can be used here. And this is probably the slowest solution of all presented in this answer.
RLIKE / REGEXP
You can also use a regular expression:
select p.*
from products p
where p.upc_variation rlike '(^|,)(12345|34567)(,|$)'
See demo of all queries on dbfiddle.uk
