php - 我的 SQL 查询在获取数据时使用异常

Question

我正在使用 MySQL 从表中获取数据，但它显示异常。这是我正在使用的代码。我使用 URL 来调用它来测试:

    $userName=mysql_real_escape_string($_GET['userName']);
    $query = mysql_query("SELECT * FROM UserCredentials where UserName='$userName' ");

http://celeritas-solutions.com/pah_brd_v1/productivo/getUserData.php?userName=jamshaid.ali

这是一个异常(exception)

Warning: mysql_fetch_assoc(): supplied argument is not a valid MySQL result resource in /home/content/i/h/u/ihus235/html/cs/pah_brd_v1/productivo/getUserData.php on line 74 []

这是完整的代码

   $userName=mysql_real_escape_string($_GET['userName']);

   $query = mysql_query("SELECT * FROM UserCredentials Where UserName='$userName' ");


    $rows = array();
    while($row = mysql_fetch_assoc($query)) {
    $rows[] = $row;
    }
    echo json_encode($rows);
     ?>    

Answer 1

$query = sprintf("SELECT * FROM UserCredentials where UserName='%s'",mysql_real_escape_string($_GET['userName']));
$result = mysql_query($query);
if(result){
   //do you code
}