Row Level Trigger for insert/update to a table Given a table ITEM as below :
CREATE TABLE ITEM (
ItemNo        int not null,
category      varchar(20) not null,
Quantity      int not null,
Price       decimal(10,2) not null,
Total       decimal(10,2) not null,
CONSTRAINT pk_item primary key (ItemNo)
);

I need to write a row-level trigger called update_item that will fire whenever Quantity and/or Price is inserted/updated. When this happens, the Total column will be set by the trigger as the product of Quantity and Price.
Any help will be appreciated.
In MySQL you need to make deferent trigger for updating and Inserting;
DELIMITER $$

CREATE TRIGGER before_ITEM _insert
BEFORE INSERT
ON ITEM FOR EACH ROW
BEGIN
   SET NEW.Total = NEW.Quantity * NEW.Price;   
END $$

DELIMITER ;

CREATE TRIGGER before_ITEM _UPDATE
BEFORE UPDATE
ON ITEM FOR EACH ROW
BEGIN
   SET NEW.Total = NEW.Quantity * NEW.Price;   
END $$

DELIMITER ;

But for that purpose you can use generated Columns like
CREATE TABLE ITEM (
ItemNo        int not null,
category      varchar(20) not null,
Quantity      int not null,
Price       decimal(10,2) not null,
Total       decimal(10,2) GENERATED ALWAYS AS (Quantity * Price),
CONSTRAINT pk_item primary key (ItemNo)
);