MySQL Query, problems with with duplicates on insert into
问题 So I'm using the forum software Xenforo and I need help with a SQL query which will be executed periodically. The forum will have approximately 300-500 active users. So nothing too big. The goal: All users xf_users need to be subscribed to node_id 71 except users which are part of certain user_group_id . Now users can unsubscribe from the forum or change the notify_on and send_alert & send_email fields. I do not want that. So if users 'unsubscribe' they need to be added again. The only