php - PHP选择语句问题与MySQL

PHP选择语句问题与MySQL

我收到此错误..

 Warning: mysql_num_rows(): supplied argument is not a valid MySQL result resource in /home/try/public_html/register.php on line 17

我的密码是

$siteAddress = trim($_POST['b_Address']);

$sql="SELECT * FROM user WHERE siteAddress='$siteAddress';";

$result=mysql_query($sql);
$count=mysql_num_rows($result);

//check for address

if($count)
{
$errorMessage = "<p><font color=red size=4>Site Address " . $siteAddress . " is not available. </font></p>";
$proceed = "no";
}

我尝试echo $ sql，我明白了

Warning: mysql_num_rows(): supplied argument is not a valid MySQL result resource in /home/try/public_html/register.php on line 17
SELECT * FROM user WHERE siteAddress='myshop';

如果我在phpmyadmin中输入sql，则会返回一些信息。

     Showing rows 0 - 0 (1 total, Query took 0.0003 sec)

最佳答案

你那里有两个分号

$sql="SELECT * FROM user WHERE siteAddress='$siteAddress';";

它应该是：

$sql="SELECT * FROM user WHERE siteAddress='" . $siteAddress ."'";

您还可以：

$sql= mysql_query("SELECT * FROM user WHERE siteAddress='" . $siteAddress ."'");
$count=mysql_num_rows($sql);