mysql - How te select records from table A which doesn't exist in table B

Question

This question already has answers here: question from:https://stackoverflow.com/questions/65903106/how-te-select-records-from-table-a-which-doesnt-exist-in-table-b

Answer 1

You need to use LEFT JOIN

SELECT *
FROM `users` as `u`
LEFT JOIN `already_selected` as `as` ON `u`.`id` = `as`.`user_id`
WHERE `as`.`user_id` IS NULL