Second Purchase Date

Problem

Return each user_id and the date of their second purchase. Users with fewer than two purchases should not appear.

Why This Matters

Retention, repeat purchase, and lifecycle questions often need the nth event, not just the first or last event.

Schema

orders(order_id INT, user_id INT, order_date TEXT)

Examples

Constraints

• Return the exact requested result.
• Handle common edge cases.
• Keep the solution readable before optimizing.