Risultato finale: | customer_id | gap_days | |-------------|----------| | 1 | 123 | | 2 | 120 | con cte come( select order_id, customer_id, order_dt, lag(order_dt) over(partition by customer_id order by order_dt) as prev_order_ft, datediff(day, prev_order_ft, order_dt) as gap_days da Orders ) selezionare customer_id, max(gap_days) come gap_days da cte dove gap_days > 60 gruppo per customer_id