Toto je předchozí dotaz s WHERE
klauzule:
SELECT gs.month, c.customer, MAX(c.order_date + interval '12 month')::date as churn_date
FROM customers c CROSS JOIN
GENERATE_SERIES('2021-03-01'::date, '2021-04-01'::date, interval '1 month') gs(month)
WHERE c.order_date < gs.month + interval '1 month'
GROUP BY gs.month, c.customer
HAVING DATE_TRUNC('month', MAX(c.order_date)) = DATE_TRUNC('month', gs.month) - interval '12 month';
Zde je db<>hudlík.