1、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 'CREATE TABLE grade(
gradeID INT(4) UNSIGNED NOT NULL PRIMARY KEY AUTO_INCR' at line 2

代码如下：

USE Myschool;

DROP TABLE IF EXISTS grade

CREATE TABLE grade(

      gradeID INT(4) UNSIGNED NOT NULL PRIMARY KEY AUTO_INCREMENT COMMENT '年级编号',

      gradeName VARCHAR(50) NOT NULL COMMENT '年级名称'

      )COMMENT="年级表";

仔细看就会发现，drop table if exists grade这一行，没有加  ';'