trigger in mysql code example
Example 1: trigger in mysql syntax
CREATE TRIGGER trigger_name
{BEFORE | AFTER} {INSERT | UPDATE| DELETE }
ON table_name FOR EACH ROW
trigger_body;
Example 2: mysql trigger example
DELIMITER $$
CREATE TRIGGER after_sales_update
AFTER UPDATE
ON sales FOR EACH ROW
BEGIN
IF OLD.quantity <> new.quantity THEN
INSERT INTO SalesChanges(salesId,beforeQuantity, afterQuantity)
VALUES(old.id, old.quantity, new.quantity);
END IF;
END$$
DELIMITER ;
Example 3: trigger in mysql
CREATE TRIGGER Product_Details_tr
BEFORE INSERT ON Product_Details
FOR EACH ROW
SET NEW.User_ID = CURRENT_USER();
Example 4: mysql create trigger
CREATE
TRIGGER `event_name` BEFORE/AFTER INSERT/UPDATE/DELETE
ON `database`.`table`
FOR EACH ROW BEGIN
END;
CREATE
TRIGGER `blog_after_insert` AFTER INSERT
ON `blog`
FOR EACH ROW BEGIN
IF NEW.deleted THEN
SET @changetype = 'DELETE';
ELSE
SET @changetype = 'NEW';
END IF;
INSERT INTO audit (blog_id, changetype) VALUES (NEW.id, @changetype);
END$$
Example 5: mysql triggers
DELIMITER $$
CREATE TRIGGER before_workcenters_insert
BEFORE INSERT
ON WorkCenters FOR EACH ROW
BEGIN
DECLARE rowcount INT;
SELECT COUNT(*)
INTO rowcount
FROM WorkCenterStats;
IF rowcount > 0 THEN
UPDATE WorkCenterStats
SET totalCapacity = totalCapacity + new.capacity;
ELSE
INSERT INTO WorkCenterStats(totalCapacity)
VALUES(new.capacity);
END IF;
END $$
DELIMITER ;