Working with mysql query to compare data with php - php

Question

I'm building a script using PHP and MySQL to compare a certain live page against older versions of it - i'm doing it by md5 hashing it and comparing it to the latest version.
Now i'm trying to pull the latest known hash of a certain page using the following:
SELECT latest_hash FROM tracked_sites WHERE domain = 'domain.com
Which shows me the actual contant of latest_hash for a certain "domain.com"
Now i'm trying to put it in a valid variable so i can compare it using the following:
$latestmd5_sql=(mysqli_query($con,"SELECT latest_hash FROM tracked_sites WHERE domain = 'domain.com'"));
Now, thinking i have the actual content of the database i'm trying to compare it with
if ((md5(file_get_contents("https://domain.com/page.html")))==$latestmd5_sql)
BUT, for some reason i get False as answer.
I've tried to print out the $latestmd5_sql var using echo or print_r but it seems to be empty or empty array, i'm a bit puzzled as to what i'm doing wrong and would love to get ideas.

Answer 1

In your provided code, $latestmd5_sql will be a resource, not the value in the database.
You'll need to "fetch" the data from the resource in order to compare values.
Here's an example to illustrate the workflow from sql code to php variable:
// your sql
$sql="SELECT latest_hash FROM tracked_sites WHERE domain = 'domain.com'";
// the query (returns a resource)
$query = mysqli_query($con,$sql);
// fetch the resulting data (this is the part you're missing)
$result=mysqli_fetch_assoc($query);
// take a look at the data (for debugging purposes)
echo"DATA:<pre>".print_r($result,true)."</pre>";
// compare
if ((md5(file_get_contents("https://domain.com/page.html")))==$result['latest_hash']) {
echo"<p>Match</p>";
} else {
echo"<p>No Match</p>";
}