Mysqli 预处理语句 stmt_num_rows returns 0

Question

出于某种原因，stmt_num_rows 总是以 0 结束。无论我使用正确的电子邮件和单词执行查询还是错误的。这是代码：

    include_once './Connect.php';

$db = new DB_Connect(); 
$con = $db->connect();

$password = $_POST["Password"]; 
$email = $_POST["Email"];  
$word = $_POST["Word"]; 
$true = 'true';  
$false = 'false';
$response = array();


$selectquery = mysqli_prepare($con, "SELECT ID FROM users WHERE Email = ? AND Word = ?");  
    mysqli_stmt_bind_param($selectquery , "ss" , $email , $word); 
    mysqli_stmt_execute($selectquery); 
    mysqli_stmt_store_result($selectquery); 
    mysqli_stmt_bind_result($selectquery, $ID);


    if (mysqli_stmt_num_rows($selectquery) > 0){ 
        $response[resp] = $true; 
        $updatequery = mysqli_prepare($con , "UPDATE users SET Password = ? WHERE Email = ? AND Word = ?"); 
        mysqli_stmt_bind_param($updatequery ,"sss", $password, $email, $word); 
        mysqli_stmt_execute($updatequery); 
        mysqli_stmt_close($updatequery);
    }else{
        $response[resp] = $false; 
    }


echo json_encode($response); 
mysqli_stmt_close($selectquery); 
mysqli_close($con);

运行下面的代码：密码、电子邮件 和Word从 android 发布。首先有一个查询来检查 table 中是否有一个用户（行）具有相应的 Email 和 Word。如果是，则添加 ID。然后调用 stmt_num_rows 来检查获取的行数，但获取的行数最终为 0（我得到的响应为 "false"）。但如果它是一个，那么将调用 UPDATE 查询并且我将收到响应 "true"。有谁知道我犯的错误？

谢谢！

Answer 1

将我们的评论添加到答案中以结束此问题：

我的：

"Try removing / commenting those out and try it again. If that fails, then your POSTs may be failing. Check for errors against those and variables, and in your query."

和：

"also make sure that no whitespace is being introduced, if so, trim() and do a var_dump. Remember that POST arrays are case-sensitive. Password and password etc. are two different animals. Same goes for the other POST arrays"

伊万的：

"Fred you were right the issue wasn't in the php it was actually the data posted. Since I'm using the Async Http library i forgot to post the actual parameters I want to send. I set the params to null"

密码

我注意到您可能以明文形式存储密码。不推荐这样做。

使用以下之一：

CRYPT_BLOWFISH
crypt()
bcrypt()
scrypt()
On OPENWALL
PBKDF2
PBKDF2 on PHP.net
PHP 5.5 的 password_hash() 函数。
兼容包（如果PHP < 5.5）https://github.com/ircmaxell/password_compat/

其他链接：

PBKDF2 For PHP

关于列长度的重要旁注：

如果您决定使用 password_hash() 或 crypt，请务必注意，如果您当前的密码列的长度低于 60，则需要将其更改为（或更高） ).手册建议长度为255。

您需要更改列的长度并使用新的散列重新开始才能生效。否则，MySQL 将默默地失败。

Mysqli 预处理语句 stmt_num_rows returns 0

Mysqli prepared statement stmt_num_rows returns 0

php

mysql

mysqli

prepared-statement