Auto-increment - automatic reset for each year

Question

MySQL/InnoDB

In my case my receipts should be counted on yearly basis; 1/2015, 2/2015 ... 556/2015 and so on. When next year comes, the counter should start from 1 a

Answer 1

After help from @RickJames the solution is:

CREATE TRIGGER ReceiptNumber BEFORE INSERT ON receipts FOR EACH ROW
BEGIN
  SET NEW.rcyear=YEAR(NOW());
  SET NEW.rcno=(SELECT IFNULL(MAX(rcno),0)+1 FROM receipts WHERE rcyear=YEAR(NOW()));
END;