Maria DB - Before Insert Trigger assign value to NEW.field - triggers

Question

i am new for this, background is totally based on Oracle and related products. i have installed XAMPP 3.3.0, i have created a trigger which works fine.
DELIMITER $$
CREATE OR REPLACE
TRIGGER bi_cancel_booking BEFORE INSERT
ON cancelled_booking
FOR EACH ROW BEGIN
--
DECLARE next_receipt VARCHAR(20);
DECLARE rct_no INT(5);
--
SELECT MAX(starting_number)+1, CONCAT(receipt_prefix,'-',MAX(starting_number)+1)
INTO rct_no, next_receipt
FROM com_receipt_types
WHERE receipt_type = 'Cancel Booking';
END$$
DELIMITER ;
but when using NEW.cancel_receipt_no (see below code) it is showing error : Error Code: 1327 Undeclared variable: NEW
DELIMITER $$
CREATE OR REPLACE
TRIGGER bi_cancel_booking BEFORE INSERT
ON cancelled_booking
FOR EACH ROW BEGIN
--
DECLARE next_receipt VARCHAR(20);
DECLARE rct_no INT(5);
--
SELECT MAX(starting_number)+1, CONCAT(receipt_prefix,'-',MAX(starting_number)+1)
INTO rct_no, NEW.cancel_receipt_no
FROM com_receipt_types
WHERE receipt_type = 'Cancel Booking';
END$$
DELIMITER ;
is there any restriction that i cannot assign the value to NEW.field as in my first code here when i am trying to assign the value as: NEW.cancel_receipt_no := next_receipt then it also showing error. please help, how i can do this here?

Answer 1

i used below code and error has gone (used SET):
SET NEW.cancel_receipt_no = next_receipt;
DELIMITER $$
CREATE OR REPLACE
TRIGGER bi_cancel_booking BEFORE INSERT
ON cancelled_booking
FOR EACH ROW BEGIN
--
DECLARE next_receipt VARCHAR(20);
DECLARE rct_no INT(5);
--
SELECT MAX(starting_number)+1, CONCAT(receipt_prefix,'-',MAX(starting_number)+1)
INTO rct_no, next_receipt
FROM com_receipt_types
WHERE receipt_type = 'Cancel Booking';
SET NEW.cancel_receipt_no := next_receipt;
END$$
DELIMITER ;
it was because of my lack of knowledge, gradually i will learn the things with help of all seniors here.