Days from First Visit to Purchase

For users who purchased, return the number of days between their first visit and purchase. Order by user_id.

Table schema

Events(user_id INT, step VARCHAR(10), event_date DATE)

Sample data

user_id | step | event_date
1 | visit | 2026-04-01
2 | visit | 2026-04-01
3 | visit | 2026-04-02
4 | visit | 2026-04-02
1 | cart | 2026-04-01
2 | cart | 2026-04-03
3 | cart | 2026-04-02
1 | purchase | 2026-04-04
3 | purchase | 2026-04-02