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HomeBackend DevelopmentPHP TutorialWarning</b> mysql_free_result(): supplied argument is not a valid MySQL result,该怎么解决

Warning: mysql_free_result(): supplied argument is not a valid MySQL result
这是什么错?

<br /><?php<br />	header('content-type:application/json;charset=utf8');<br />	$host = '127.0.0.1:3307';<br />	$root = 'root';<br />	$pwd = 'apeg1996';<br /><br />	$con = mysql_connect($host,$root,$pwd);<br />	if($con == false){<br />		echo "连接数据库失败!"; <br />	}else{ <br />		echo "连接数据库成功!";<br />	}<br /><br />	$sql = "select * from user";<br />	function execute_data($sql){<br />		$result = mysql_query($sql);<br />		mysql_free_result($result);<br />		mysql_close($conn);<br />		return $result;<br />	}<br />	echo execute_data($sql);<br />?><br />


已显示连接成功,但是报这个错。。
<br />连接数据库成功!<br /><br /><b>Warning</b>:  mysql_free_result(): supplied argument is not a valid MySQL result resource in <b>F:\environment\WAMP\wamp5\wamp\wamp\www\test\sql.php</b> on line <b>17</b><br /><br /><br /><br /><b>Warning</b>:  mysql_close(): supplied argument is not a valid MySQL-Link resource in <b>F:\environment\WAMP\wamp5\wamp\wamp\www\test\sql.php</b> on line <b>18</b><br /><br />

------解决思路----------------------
你只连接了数据库系统,但没有选择待操作的数据库
mysql_select_db('库名');
否则怎么知道你在查询那个库中的 user 表呢?

另外,你的 mysql_close($conn) 在函数中,而 $conn 并未传到函数中。
所以会有第2条错误
------解决思路----------------------

本帖最后由 fdipzone 于 2015-03-15 00:05:08 编辑
引用:
Quote: 引用:

$result = mysql_query($sql);
改为
$result = @mysql_query($sql) or die(mysql_error());


网页上显示的是No database selected, 这个是没有找到这个数据库吗?
但是我用的是Navicat 8 for mysql 这个视图工具。
我在这里面创建的数据库,并简历了表。 我应该怎么去查询这个数据库里的表呢?


你在mysql_query之前没有mysql_select_db,mysql不知道你需要在哪个db中执行查询操作。

在创建连接后,加一句
 @mysql_select_db('这里填写数据库名',$conn) or die(mysql_error());

<br /><?php<br />    header('content-type:application/json;charset=utf8');<br />    $host = '127.0.0.1:3307';<br />    $root = 'root';<br />    $pwd = 'apeg1996';<br /> <br />    $con = mysql_connect($host,$root,$pwd);<br />    if($con == false){<br />        echo "连接数据库失败!"; <br />    }else{ <br />        echo "连接数据库成功!";<br />    }<br /> <br />    @mysql_select_db('这里填写数据库名',$conn) or die(mysql_error());	 // 加入这句<br /><br />    $sql = "select * from user";<br />    function execute_data($sql, $conn){ // 加入$conn 参数<br />        $result = mysql_query($sql);<br />        mysql_free_result($result);<br />        mysql_close($conn);<br />        return $result;<br />    }<br />    echo execute_data($sql, $conn);<br />?><br />
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