警告问题：期望参数1为mysqli_result [重复]

Question

这个问题已经在这里有了答案 ：

mysqli_fetch_assoc（）期望参数/调用成员函数bind_param（）错误。如何获取并修复实际的mysql错误？ （1个答案）

上个月关闭。

我收到下面列出的以下警告，我想知道如何解决它

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

该代码围绕下面列出的PHP代码这一部分。如果需要，我可以列出完整的代码。

// 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 1

mysqli_query()``FALSE如果查询中有错误，则返回。所以你应该测试一下…

/* 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();
}

请参阅此链接以获取mysqli_query参考
http://php.net/manual/zh/mysqli.query.php