创建一个触发器出现4个错误1064

问题遇到的现象和发生背景

问题相关代码，请勿粘贴截图

sql
CREATE TRIGGER repairtrigger ON repairform
FOR INSERT 
AS 
BEGIN
    DECLARE@dor_id INT,@product_id VARCHAR(100);
    SELECT@dor_id=dor_id,@product_id=product_id
    FROM inserted
IF EXISTS
    (
        SELECT * FROM stu_information AS S,products AS P
        WHERE S.dor_id=P.dor_id AND S.stu_id=@stu_id AND P.product_id=@product_id
    )
    BEGIN
        print'报修单合格';
    END
ELSE
    BEGIN
        print'报修单不合格';
        ROLLBACK ;
    END
END

运行结果及报错内容

5 queries executed, 1 success, 4 errors, 0 warnings

查询：create trigger repairtrigger on repairform for insert as begin declare@dor_id int,@product_id VARCHAR(100)

错误代码： 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 'on repairform
for insert
as
begin
declare@dor_id int,@product_id VARCHAR(100)' at line 1

执行耗时 : 0 sec
传送时间 : 0 sec
总耗时 : 0 sec
查询：select@dor_id=dor_id,@product_id=product_id from inserted if exists ( select * from stu_information as S,products as P where S.d

错误代码： 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 exists
(
select * from stu_information as S,products as P
where S.dor_id' at line 3

执行耗时 : 0 sec
传送时间 : 0 sec
总耗时 : 0 sec
查询：end else begin print'报修单不合格'

错误代码： 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 'end
else
begin
print'报修单不合格'' at line 1

执行耗时 : 0 sec
传送时间 : 0 sec
总耗时 : 0 sec
错误代码： 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 'end
end' at line 1

执行耗时 : 0 sec
传送时间 : 0 sec
总耗时 : 0 sec

我的解答思路和尝试过的方法

我想要达到的结果

您的SQL语法有错误