php - warning problem: expects parameter 1 to be mysqli_result

I get
the following warning listed below and I was wondering how do I fix
it

Warning: mysqli_fetch_array()
            expects parameter 1 to be mysqli_result, boolean given on line
            65

The code
is around this section of PHP code listed below. I can list the full code if
needed.

// function to retrieve
            average and votes
function getRatingText(){
 $dbc = mysqli_connect
            ("localhost", "root", "", "sitename");
 $sql1 = "SELECT COUNT(*) 

            FROM articles_grades 
 WHERE users_articles_id =
            '$page'";


 $result =
            mysqli_query($dbc,$sql1);
 $total_ratings =
            mysqli_fetch_array($result);

 $sql2 = "SELECT COUNT(*) 

            FROM grades 
 JOIN grades ON grades.id = articles_grades.grade_id

            WHERE articles_grades.users_articles_id = '$page'";

 $result =
            mysqli_query($dbc,$sql2);
 $total_rating_points =
            mysqli_fetch_array($result);

 if (!empty($total_rating_points)
            && !empty($total_ratings)){
 $avg = (round($total_rating_points /
            $total_ratings,1));
 $votes = $total_ratings;
 echo $avg . "/10 (" .
            $votes . " votes cast)";
 } else {
 echo '(no votes
            cast)';
 }
}

Answer

mysqli_query()
returns FALSE if there was an error in the query. So you should
test for it...

/* Select queries
            return a resultset */
if ($result = mysqli_query($dbc, "SELECT Name FROM City
            LIMIT 10")) {
 printf("Select returned %d rows.\n",
            $result->num_rows);

 /* free result set */

            $result->close();
}

See
this link for the mysqli_query reference
href="http://php.net/manual/en/mysqli.query.php"
rel="noreferrer">http://php.net/manual/en/mysqli.query.php