https://jinhokwon.github.io/mysql/mysql-select-for-update/ MySQL SELECT FOR UPDATE 의 이해 1. SELECT FOR UPDATE jinhokwon.github.io delimiter // create procedure withdraw(in account_id int, in amount numeric(7, 2), out success bool) begin declare current_balance numeric(7, 2) default 0.0; start transaction; select balance into current_balance from accounts where id=account_id for update; if current..