MYSQL官方免费手册中已经有现成的例子了。 CREATE TABLE test1(a1 INT); CREATE TABLE test2(a2 INT); CREATE TABLE test3(a3 INT NOT NULL AUTO_INCREMENT PRIMARY KEY); CREATE TABLE test4( a4 INT NOT NULL AUTO_INCREMENT PRIMARY KEY, b4 INT DEFAULT 0 );delimiter |CREATE TRIGGER testref BEFORE INSERT ON test1 FOR EACH ROW BEGIN INSERT INTO test2 SET a2 = NEW.a1; DELETE FROM test3 WHERE a3 = NEW.a1; UPDATE test4 SET b4 = b4 + 1 WHERE a4 = NEW.a1; END; |delimiter ;INSERT INTO test3 (a3) VALUES (NULL), (NULL), (NULL), (NULL), (NULL), (NULL), (NULL), (NULL), (NULL), (NULL);INSERT INTO test4 (a4) VALUES (0), (0), (0), (0), (0), (0), (0), (0), (0), (0);Suppose that you insert the following values into table test1 as shown here
CREATE TABLE test1(a1 INT);
CREATE TABLE test2(a2 INT);
CREATE TABLE test3(a3 INT NOT NULL AUTO_INCREMENT PRIMARY KEY);
CREATE TABLE test4(
a4 INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
b4 INT DEFAULT 0
);delimiter |CREATE TRIGGER testref BEFORE INSERT ON test1
FOR EACH ROW BEGIN
INSERT INTO test2 SET a2 = NEW.a1;
DELETE FROM test3 WHERE a3 = NEW.a1;
UPDATE test4 SET b4 = b4 + 1 WHERE a4 = NEW.a1;
END;
|delimiter ;INSERT INTO test3 (a3) VALUES
(NULL), (NULL), (NULL), (NULL), (NULL),
(NULL), (NULL), (NULL), (NULL), (NULL);INSERT INTO test4 (a4) VALUES
(0), (0), (0), (0), (0), (0), (0), (0), (0), (0);Suppose that you insert the following values into table test1 as shown here