Question

I wrote my own trigger today but when I enter it on mysql it give me the syntax error.
Here is the my trigger definition in the following code;

CREATE DEFINER = CURRENT_USER TRIGGER `Customer_Car_Trigger` AFTER INSERT ON `CUSTOMERS`
FOR EACH ROW
BEGIN
SET @CountOfCar = (SELECT COUNT(ID) FROM `CARS`,`CUSTOMERS` WHERE `CARS`.`CustomerID` = `CUSTOMERS`.`ID`)
IF @CountOfCar>0 THEN
    UPDATE `CUSTOMERS` SET `NumberOfCars`=+1 WHERE `CUSTOMERS`.`ID`=NEW.`ID`
END IF
END;

When I put this code into phpmyadmin it gives me:

#1064 – You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ‘IF @CountOfCar>0 THEN UPDATE CUSTOMERS SET NumberOfCars=+1
WHERE `CUSTOMER’ at line 5

I tried many different things to IF statement.Am I doing wrong? I didnt show any syntax error. Why phpmyadmin gives me this error to me? Is it different to veriable in IF-ELSE statements.

Answer 1

You forgot a few ; and to iterate by 1 in SQL you can’t use +=1

delimiter |
CREATE DEFINER = CURRENT_USER TRIGGER `Customer_Car_Trigger` AFTER INSERT ON `CUSTOMERS`
FOR EACH ROW
BEGIN
   SET @CountOfCar = (SELECT COUNT(ID) FROM `CARS`,`CUSTOMERS` WHERE `CARS`.`CustomerID` = `CUSTOMERS`.`ID`);
   IF @CountOfCar>0 THEN
      UPDATE `CUSTOMERS` SET `NumberOfCars`= `NumberOfCars`+1 WHERE `CUSTOMERS`.`ID`=NEW.`ID`;
   END IF;
END;
|
delimiter ;