遇到的非数字值的SQL解决方法

Question

I see that there's an issue with PHP showing the following error:

Warning: A non-numeric value encountered in on line

This is my code, I just want to pull an entry from the database with a unique ID number.

include("database_connection_information.php");     
$article_id = 2;
$sql = "SELECT article_title, article_text 
        FROM Articles 
        WHERE article_id = " + intval($article_id);
$result = $conn->query($sql);

This code as it is generates the error.

(Warning: A non-numeric value encountered describes the issue, but doesn't say how to work around it)

Answer 1

it is necessary to merge with a dot, not with a plus.

include("database_connection_information.php"); 

$article_id = 2;
$sql = "SELECT article_title, article_text 
        FROM Articles 
        WHERE article_id = ".$article_id;
$result = $conn->query($sql);