php 为什么我会收到 MySQL 错误“查询为空”？
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/636032/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
Why do I get the MySQL Error "Query was empty"?
提问by Greg
$id = $_REQUEST['id'];
$Section = $_REQUEST['section'];
$Subject = $_REQUEST['subject'];
$type = $_REQUEST['type'];
$Start_date1 = isset($_REQUEST['startTxt'])?($_REQUEST['startTxt']):"";
$Venue = isset($_REQUEST['venTxt'])?($_REQUEST['venTxt']):"";
$Facilitator = isset($_REQUEST['faciTxt'])?($_REQUEST['faciTxt']):"";
$Level = isset($_REQUEST['lvlLst'])?($_REQUEST['lvlLst']):"";
$Date1 = $_REQUEST['date1'];
if(isset($_REQUEST['EDIT']))
{
mysql_query("UPDATE service SET Start_date='$Date1', Venue='$Venue', Facilitator='$Faci' WHERE ServiceID ='$id'");
if (!mysql_query($sql,$con))
{
die('Error: ' . mysql_error());
}
echo '<script type="text/javascript">';
echo 'alert("Changes have been save!");';
echo 'window.location="Admin_RecSchedMapLst.php";';
echo '</script>';
mysql_close($con);
}
When I click save it returns "Error: Query was empty" - why is this?
当我单击保存时，它返回“错误：查询为空”——这是为什么？
回答by Greg
You're calling mysql_query()twice, once with a non-existent $sqlparameter:
您调用了mysql_query()两次，一次使用不存在的$sql参数：
mysql_query("UPDATE service SET Start_date='$Date1', Venue='$Venue', Facilitator='$Faci' WHERE ServiceID ='$id'");
if (!mysql_query($sql,$con))
should be:
应该：
if (!mysql_query("UPDATE service SET Start_date='$Date1', Venue='$Venue', Facilitator='$Faci' WHERE ServiceID ='$id'"))
You're also not escaping your input, leaving you open to SQL injection.
You should use bound parameters ideally, or at the very least run your parameters through mysql_real_escape_string().
你也没有逃避你的输入，让你对 SQL 注入持开放态度。理想情况下，您应该使用绑定参数，或者至少通过mysql_real_escape_string().
For example:
例如：
$Date1 = mysql_real_escape_string($Date1, $conn);
回答by Paul Tarjan
回答by jonstjohn
You are not setting the $sql variable and calling mysql_query() twice.
您没有设置 $sql 变量并两次调用 mysql_query() 。
