Task: to execute a query that depends on the execution of an in operator request That is, the request will be made from the admin panel of a certain super-user who has a list of other referral users who were previously registered with him. It is necessary that when deleting it is checked whether there is a referral in the super-user list.
Sample code:
DELETE FROM (`users`) WHERE `user_id` IN (SELECT `user_id` FROM `users` WHERE `referrals` = `super_user_id`) AND `status` = '1' Table users
| user_id | referrer_id | name | status | ----------------------------------------- | 1000 | 0 | user1 | 1 | ----------------------------------------- | 1001 | 0 | user2 | 1 | ----------------------------------------- | 1002 | 0 | user3 | 0 | ----------------------------------------- | 1010 | 1000 | user4 | 1 | ----------------------------------------- | 1020 | 1000 | user5 | 1 | -----------------------------------------
In this case, the super-user (referrer_id = 0) with user_id = 1000 has two referrals user_id (1010 , 1020) . When deleting any of them, you need to check whether they are the referrals of the user with user_id = 1000. Because when deleting, you can specify the value of user_id = 1001 and delete another super-user.
delete A.* from users A JOIN users B on ....