将数据插入mysql db时，Null Php变量(Null Php Variable when inserting data into mysql db)

 所以我正在使用Web服务开发一个Android项目。 我有一些问题，比如在我的数据库中插入一些数据时，我的php无法识别变量或类似的东西，它确实为数字插入值“0”，并且在使用邮递员测试后为字符串插入空格，甚至是应用本身。 
 
 这是我的PHP文件内容： 
 
<?php
$con = mysqli_connect("...","...","...","...");

    $card_number = $_POST["card_number"];

    $query = "INSERT INTO card (card_number,card_solde,date_exp) VALUES ('$card_number',0,2024)";

    mysqli_query($con,$query) or die(mysqli_error($con));

    $response = array();
    $response["success"] = true;  
    echo json_encode($response);

    mysqli_close($con);
?>
 
 这是表模式的图像和插入的结果。 https://imgur.com/aJvdbxF 
 
 谢谢youuu :)） 

So i'm working on an Android project using web services. I've got some problems like while inserting some data in my db, my php doesn't recognize the variable or something like that and it does insert value "0" for numbers and a blank space for Strings after testing with postman or even the app itself.
 
Here's my PHP file content :
 
<?php
$con = mysqli_connect("...","...","...","...");

    $card_number = $_POST["card_number"];

    $query = "INSERT INTO card (card_number,card_solde,date_exp) VALUES ('$card_number',0,2024)";

    mysqli_query($con,$query) or die(mysqli_error($con));

    $response = array();
    $response["success"] = true;  
    echo json_encode($response);

    mysqli_close($con);
?>
 
Here's an image for the table schema and the result of the insertion. https://imgur.com/aJvdbxF
 
Thank youuu :))

原文：https://stackoverflow.com/questions/37148574