Multiple unwanted records in Group by clause in Postgress

Question

I have two table and I am joining them together then running a group by clause. The problem is that I keep getting unwanted data.

client table
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Answer 1

If you want the first one in each company, then use distinct on. This is a nice construct available only in Postgres:

SELECT DISTINCT ON (co.name) co.name, cl.name, cl.created_at
FROM company co INNER JOIN
     client cl
     ON cl.company_id = co.id
ORDER BY co.name, cl.created_at asc;