MySQL match brand of item that you don't know brand of?

Question

Say I have a table that has id and brand columns.

Say I have an item I know the ID is 300, but that's all I know. Is there a way to make a query pull all the items with the same brand as the item, or do I have to break it into 2 queries and first select the brand of item 300?

Thanks.

Answer 1

select id
from item
where brand = (select brand from item where id = 300)

Answer 2

If I understood you correctly, using a subselect might be the easiest way to solve that problem.

SELECT * FROM mytable WHERE brand = (SELECT brand FROM mytable WHERE id = 300 );

Answer 3

You can join the table to itself:

select
    a.*
from
    brands a
    inner join brands b on
        a.brand = b.brand
where
    b.id = 300

Answer 4

select * from products where category in (select category from products where Id = 300)