GROUP or DISTINCT after JOIN returns duplicates

Question

I have two tables, products and meta. They are in relation 1:N where each product row has at least one meta row via foreign key.

(viz. SQLf

Answer 1

Use distinct on as suggested by @Craig's answer but combined with the order by clause as explicated in the comments. SQL Fiddle

select distinct on(m.product_id) * 
from
    meta m
    inner join
    products p on p.id = m.product_id
order by m.product_id, m.id desc;