How to return only those rows that don't have an associated row in another table?

Question

MySQL

There are two tables person and sms. Linked to each other by id. Almost all person strings have an associated sms string. But some person strings don't have sms string yet, how to return only those person strings?

Answer 1

SELECT person.*
FROM person
LEFT JOIN sms ON sms.id = person.id
WHERE sms.id IS NULL

Answer 2

In the query, link two tables LEFT OUTER JOIN and put a filter on an empty sms.