SELECT u.email,c.name as post_category
FROM posts p
left join user_emails u on p.user_id = u.user_id
left join topics t on p.topic_id=t.id
left join categories c on t.category_id = c.id
where p.created_at < '2021-03-01T00:00:00.000Z'
GROUP BY
u.email,u.user_id,c.name
SELECT u.email, c.name AS post_category, '/t/-' || t.id || '/' || p.post_number AS post_url
FROM posts p
LEFT JOIN user_emails u ON p.user_id = u.user_id
LEFT JOIN topics t ON p.topic_id = t.id
LEFT JOIN categories c ON t.category_id = c.id
WHERE p.created_at < '2021-03-01T00:00:00.000Z'
GROUP BY
u.email, u.user_id, c.name