com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException错误求助！

com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: 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 'set sex='?”·',set major='è????—???',set classes='111'set tel='123456'' at line 1
错误代号如上，对应的程序代码是：

try {
stmt=conn.createStatement();
StringBuffer sql=new StringBuffer("update student set name='");
sql.append(stu.getName()).append("',set sex='").append(stu.getSex()).append("',set major='").append(stu.getMajor()).append("',set classes='").append(stu.getClasses()).append("'set tel='").append(stu.getTel()).append("'");
stmt.executeUpdate(sql.toString());
} catch (SQLException e) {
e.printStackTrace();
}finally{
try {
stmt.close();
DBUtil.close(conn);
} catch (SQLException e) {
e.printStackTrace();
}
}

这部分到底是哪里出错了呢？还请各位帮帮忙，最后的难关了！

：select * from user where id=1 limit 0,10这种写法是没错的，不过你传的参数错了，你看错误“check the manual that corresponds to your MySQL server version for the right syntax to use near '-5,5' at line 1”你的startno传的是-5这里这个...