给本站的 WordPress 绘制了一个评论统计图！点击这里预览。代码主要是通过查询网站数据库，把输出的数据格式化，然后调用 Google Chart Api 绘制图形。

使用方法是新建一个页面模板，在类似 < ?php the_content();?> 前添加以下代码。

<script type="text/javascript" src="https://www.google.com/jsapi"></script>
    <h2>活跃用户排名</h2>
    <div id="chart_user_div" style="width:100%; height: 460px; margin: auto;"></div>
    <h2>评论数量折线图</h2>
    <div id="chart_day_div" style="width:100%; height: 500px; margin: auto;"></div>
    <h2>评论数量柱状图</h2>
    <div id="chart_month_div" style="width:100%; height: 500px; margin: auto;"></div>
        <?php
            global $wpdb;
            $numbers_day   = 120;
            $numbers_month = 13;
            $numbers_user  = 12;
            $query_day  ="SELECT COUNT(*) AS `cnt` , DATE_FORMAT( `comment_date` , '%Y-%m-%d' ) AS d FROM $wpdb->comments GROUP BY d ORDER BY `d` DESC LIMIT 0 , " . $numbers_day;
            $query_month="SELECT COUNT(*) AS `cnt` , DATE_FORMAT( `comment_date` , '%Y-%m' )    AS d FROM $wpdb->comments GROUP BY d ORDER BY `d` DESC LIMIT 0 , " . $numbers_month;
            $query_user ="
                SELECT
                COUNT( comment_author_email ) AS number,
                comment_author_email,
                comment_author
            FROM (
                SELECT *
                FROM $wpdb->comments
                LEFT OUTER JOIN $wpdb->posts
                ON ( $wpdb->posts.ID = $wpdb->comments.comment_post_ID )
                WHERE
                        comment_date > date_sub( NOW(), INTERVAL 360 DAY )
                    AND user_id = '0'
                    AND comment_approved =  '1'
                ORDER BY comment_ID DESC
            ) AS tempcmt
            GROUP BY comment_author_email
            ORDER BY number DESC
            LIMIT {$numbers_user}";
        $output_day   = $wpdb->get_results($query_day);
        $output_month = $wpdb->get_results($query_month);
        $output_user  = $wpdb->get_results($query_user);
    ?>
    <script type="text/javascript">
        google.load("visualization", "1", {packages:["corechart"]});
        google.setOnLoadCallback(drawChart_day);
        google.setOnLoadCallback(drawChart_month);
        google.setOnLoadCallback(drawChart_user);
        function drawChart_day() {
            var data = google.visualization.arrayToDataTable([
            ['date', 'comments'],
            <?php foreach (array_reverse($output_day) as $o) {echo "['" . $o->d . "'," . $o->cnt . "],";} ?>
            ]);
            var options = {
                title: '每日评论数图'
            };
            var chart = new google.visualization.LineChart(document.getElementById('chart_day_div'));
            chart.draw(data, options);
        }
        function drawChart_month() {
            var data = google.visualization.arrayToDataTable([
            ['date', 'comments'],
            <?php foreach (array_reverse($output_month) as $o) {echo "['" . $o->d . "'," . $o->cnt . "],";} ?>
            ]);
            var options = {
                title: '每月评论数图'
            };
            var chart = new google.visualization.ColumnChart(document.getElementById('chart_month_div'));
            chart.draw(data, options);
        }
        function drawChart_user() {
            var data = google.visualization.arrayToDataTable([
            ['comment_author', 'comments'],
            <?php foreach ($output_user as $o) {echo "['" . $o->comment_author . "'," . $o->number . "],";} ?>
            ]);
            var options = {
                title: '一年内最活跃用户图'
            };
            var chart = new google.visualization.PieChart(document.getElementById('chart_user_div'));
            chart.draw(data, options);
        }
</script>

其中以上引用的 js 文件由于使用了谷歌家的服务可能会无法访问，可以下载到本地后再引用比如本站是这样的：

  <script type="text/javascript" src="<?php echo get_template_directory_uri(); ?>/js/jsapi.js"></script>

这是一个很酷的功能，比起简单的文字输出，更加直观清晰，并且可以做其他统计。

刚刚发现手机浏览器没办法显示绘制的图，也不知道哪里错了。