mysqli_fetch_row() not displaying after foreach() in PHP - php

Question

when a foreach is followed by a mysqli_fetch_row displaying the same query results, the mysqli_fetch_row() doesn't display. However if the mysqli_fetch_row is executed before the foreach() both are displayed. Why is this?
QUERY:
<?php
$connection = mysqli_connect("localhost", "root", "", "login_app");
$query = "SELECT *
FROM users";
$result = mysqli_query($connection, $query);
if(!$result){
die("db connection failed " . mysqli_error());
}
?>
ONLY DISPLAYS THE RESULTS OF FOREACH:
<?php
foreach($result as $results){
echo "User ID: " . $results['userID'] . "<br>";
echo "Username: " . $results['userName'] . "<br>";
echo "Password: " . $results['password'] . "<br>";
};
$row = mysqli_fetch_row($result);
print_r($row);
?>
DISPLAYS RESULTS OF BOTH FOREACH AND MYSQLI_FETCH_ROW:
<?php
$row = mysqli_fetch_row($result);
print_r($row);
foreach($result as $results){
echo "User ID: " . $results['userID'] . "<br>";
echo "Username: " . $results['userName'] . "<br>";
echo "Password: " . $results['password'] . "<br>";
};
?>

Answer 1

Executing a SELECT query with mysqli_query returns an mysqli_result object. That object implements Traversable, which is why you're able to use a foreach loop to display the results.
foreach($result as $results){ ...
is basically a handier way of doing
while ($results = mysqli_fetch_row($result)) { ...
(See Example #3 here.)
Either way you do it, you're fetching all the results, and when you get to the end of the result set $results will hold the last value fetched (null).

Answer 2

From the manual:
Fetches one row of data from the result set and returns it as an enumerated array, where each column is stored in an array offset starting from 0 (zero). Each subsequent call to this function will return the next row within the result set, or NULL if there are no more rows.
By iterating the result set with your foreach loop, you are effectively exhausting all of the row which is why no data is available on any subsequent row fetches after the loop.