Can you provide code that uses a left join?

Sure! Suppose you have two tables: requests_sent (id, user_id, sent_date) and requests_accepted (id, user_id, accepted_date). To list all sent requests and indicate whether they were accepted, you can use:

SELECT
    s.id AS request_id,
    s.user_id,
    s.sent_date,
    a.accepted_date
FROM
    requests_sent s
LEFT JOIN
    requests_accepted a
ON
    s.id = a.id;

This LEFT JOIN keeps every row from requests_sent. If a matching row exists in requests_accepted, accepted_date will be populated; otherwise it will be NULL. This pattern is useful for calculating acceptance rates, generating reports, or identifying pending requests.