WITH profiles AS (

       SELECT u.user_id as user_id,

              DATE_TRUNC('month', MIN(e.event_time))::date AS start_date

       FROM tools_shop.events as e

       JOIN tools_shop.users as u ON e.user_id = u.user_id

       JOIN tools_shop.orders as o ON o.user_id = u.user_id

       GROUP BY u.user_id)

SELECT DISTINCT

p.start_date,

p.user_id

FROM profiles as p

JOIN tools_shop.events as e ON e.user_id = p.user_id