Data Analysis and Requirements Translation Questions

-- params: @start_date, @end_date, @campaigns_csv, @countries_csv
CREATE OR REPLACE FUNCTION reporting.weekly_conversions(
  start_date date, end_date date, campaigns text, countries text
) RETURNS TABLE(campaign text, country text, conversions int, week_start date) AS $$
BEGIN
  RETURN QUERY
  SELECT c.campaign, t.country, COUNT(*) AS conversions, date_trunc('week', ev.event_date)::date AS week_start
  FROM events ev
  JOIN campaigns c ON ev.campaign_id = c.id
  JOIN territories t ON ev.country_code = t.code
  WHERE ev.event_date BETWEEN start_date AND end_date
    AND (c.name = ANY(string_to_array(campaigns, ',')) OR campaigns = '')
    AND (t.country = ANY(string_to_array(countries, ',')) OR countries = '')
  GROUP BY c.campaign, t.country, week_start;
END; $$ LANGUAGE plpgsql;

-- analytics events table
SELECT DATE(CONVERT_TZ(created_at,'+00:00','America/Los_Angeles')) AS signup_date,
       COUNT(DISTINCT user_id) AS signups
FROM analytics.events
WHERE event_name = 'signup'
  AND created_at BETWEEN '2025-11-01' AND '2025-11-30'
GROUP BY signup_date;

SELECT DATE(registration_time) AS reg_date, COUNT(DISTINCT crm_id) FROM crm.users
WHERE registration_time BETWEEN '2025-11-01' AND '2025-11-30'
GROUP BY reg_date;

SELECT a.user_id, a.created_at AS event_time, c.crm_id, c.registration_time
FROM analytics.events a
LEFT JOIN crm.users c ON a.user_id = c.user_id
WHERE a.event_name='signup' AND a.created_at BETWEEN ...;