CREATE TABLE test7(
id INT,
last_name VARCHAR(15),
salary DECIMAL(10,2) DEFAULT 2998
)ENGINE = INNODB AUTO_INCREMENT = 1 CHARACTER SET = utf8;
)ENGINE = INNODB AUTO_INCREMENT = 1 DEFAULT(此处!!) CHARACTER SET = utf8;
创建表时,上述两种方式,其中 DEFAULT 的作用是什么,测试过可以不加