First Repeat Purchase Within Thirty Days

What you will practice

For each customer, identify the first completed purchase and the first completed purchase after it. Same-time purchases are sequenced by purchase_id. Return customers whose first repeat occurs within 30 calendar days inclusive, with first_purchase_id, repeat_purchase_id and days_to_repeat. Cancelled purchases do not count. Return columns: customer_id, first_purchase_id, repeat_purchase_id, days_to_repeat.

Difficulty

Advanced

SQL concept

CTE