Converting 'String' value from MySQL table into Interger - php

Question

I am writing some script in attempt to convert a "String" value, which is retrieved from a MySQL database table, into an INTEGER, which I will then use within my PHP code.
The PHP Select-statement:
Code:
$my_number = "SELECT my_number from numbers_table where login = '".$_SESSION['login']."'";
$result_my_number = mysqli_query($conn,$my_number);
$converted_number = ($result_my_number + 20); // add 20 to my_number
echo $converted_number;
This results in nothing...
I done some research and attempted this:
Code:
$converted_number = ((int)$result_my_number) + 20; // convert my_number into an INTEGER
Also did not get any thing from this, neither a error message.
So I thought I would extract everything from the table, into an array:
Code:
$my_number = "SELECT * from numbers_table where login = '".$_SESSION['login']."'";
$result_my_number = mysqli_query($conn,$my_number);
$row_my_number = mysqli_fetch_array($result_my_number);
if ($row_my_number) {
$actual_number = $row_my_number['my_number'];
}
$final_number = ($actual_number + 20);
echo $final_number;
And also did not get anything from this. Just a blank screen.

Answer 1

You need to use mysqli_fetch_row() to get the number from the database.
$my_number = "SELECT my_number from numbers_table where login = '".$_SESSION['login']."'";
$result = mysqli_query($conn,$my_number);
$row = mysqli_fetch_row($result);
$result_my_number = $row['my_number'];
$converted_number = ($result_my_number + 20); // add 20 to my_number
echo $converted_number;