如果我们的GET值中有'.'符，我们直接写会报错。解决办法是把'.'换成'_'符号，比如这个地址localhost/test.php?a.b=123，test.php的代码如下所示：
echo $_GET['a.b'];
得到的会是"Undefined index: a.b"这样一个错误，解决办法是换成echo $_GET['a_b']即可
SQL语句执行错误：SELECT * FROM emlog_sort where pid= ORDER BY sid ASC, taxis asc
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 'ORDER BY sid ASC, taxis asc' at line 1