仅从mysql数据库“XCODE”检索具有特定数据（编号）的行

Im facing an issue with retrieving data from mysql database.

In my database, I have several columns which stand for different values. The problematic column is the one with ID (userNumber), where in many cases are these numbers different. For example, I want to download the whole rows where userNumber = 5. To this point, is everything working fine, because in my php file Ive got something like this :

$UserNumber = "5";
            $query = "SELECT * FROM test WHERE UserNumber = '$UserNumber'";

But here comes the issue. I want the users to insert this number into textfield (in app) and then this number is sent to php file where it downloads only rows where UserNumber = 5("TextFieldName").

I know, its silly question, but I am facing this issue for several weeks and I couldn't find my answer on the internet. Thanks in advance.