Stored Procedures

DELIMITER //
CREATE PROCEDURE transfer_funds(
  IN from_id INT,
  IN to_id   INT,
  IN amount  DECIMAL(10,2)
)
BEGIN
  DECLARE EXIT HANDLER FOR SQLEXCEPTION
  BEGIN
    ROLLBACK;
    RESIGNAL;
  END;

  START TRANSACTION;
  UPDATE accounts SET balance = balance - amount WHERE id = from_id;
  UPDATE accounts SET balance = balance + amount WHERE id = to_id;
  COMMIT;
END //
DELIMITER ;

-- Call and inspect
CALL transfer_funds(1, 2, 50.00);
SHOW CREATE PROCEDURE transfer_funds;
DROP PROCEDURE transfer_funds;