ช่วยหน่อยครับ ได้ลองทำการฟใช้ในการแสดงตวามเปลี่ยนแปลงของสถิติโดยใช้ api จาก highcharts. ครับ

<meta charset="utf-8" />
<?php

require './config.php';

if (!$logged_in) {
	header('Location: login.php');	
	exit();
}

if (!empty($_GET['user'])) {
	$user_data = user_data($_GET['user']);
}

if (!isset($user_data) || !$user_data) {
	$user_data = $login_data;	
}

?>

<?php echo !empty($_GET['user']) ? '<a href="./show_graph_all.php">[<< BACK]</a> ':''; ?>
<a href="./dashboard.php">[Dashboard]</a>
<h1>Stat graph of <?php echo $user_data['first'].' '.$user_data['last']; ?></h1>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.2.0/jquery.min.js"></script>
<script src="http://code.highcharts.com/highcharts.js"></script>
<script>
$(document).ready(function() {
    <?php foreach ($distances as $d) {
	
	$q = $db->prepare('
		select `match`.`name`, `match`.`date`, `stat`.`stroke`, `stat`.`time`
		from `match`
		inner join `stat` on `match`.`id` = `stat`.`match_id`
		inner join `swimmer` on `stat`.`user_id` = `swimmer`.`id`
		where `swimmer`.`id` = :ui and `stat`.`distance` = :d
		order by `match`.`date` asc
	');
	
	$q->bindParam(':ui', $user_data['id']);
	$q->bindParam(':d', $d);
	
	$q->execute();
	
	$gd = $q->fetchAll(PDO::FETCH_ASSOC);
	$gdst = array();
	
	foreach ($gd as $r) {
		$gdst[(int)$r['stroke']][] = $r;	
	}
		
	//var_dump($gdst);
	?>
	$('#graph-<?php echo $d; ?>').highcharts({
        chart:{
            zoomType:'xy',
        },
		title: {
            text: 'Distance: <?php echo $d; ?>m'
        },
        yAxis: {
			title: {
				text: 'Time'
			},
            type: 'datetime',
            dateTimeLabelFormats: {
                millisecond: '%M:%S.%L'
            }
        },
		xAxis: {
			title: {
				text: 'Match'
			},
			categories: [
				<?php foreach ($gd as $r) { ?>
				'<?php echo $r['name']; ?>',
				<?php } ?>
			]
		},
        series: [
		<?php foreach ($strokes as $k => $st) { 
			if (array_key_exists($k, $gdst)) {
		?>
			{
				name: '<?php echo $st; ?>',
				data: [
					<?php foreach ($gdst[$k] as $r) { 
					 	echo ($r['time']*1000) . ',';
					 } ?>
				],
				//pointStart: 1, 
			},
		<?php } } ?>
		]
    });
	<?php } ?>
});
</script>

<?php foreach ($distances as $d) { ?>
<div id="graph-<?php echo $d; ?>"></div>
<?php } ?>