<?php
//I'm doing this function so I don't have to keep typing the query over again
function getCalendarDay($day,$spaces){
	global $db;
	$count = $db->query("SELECT day FROM users WHERE day = ?",array($day))->count();
	$remaining = $spaces - $count;
	//if you never want it to show negative numbers, use this,otherwise comment it out.
	if($remaining < 0 ){$remaining = 0;}
	return $remaining;
}


$spaces = 6; //how many spaces do you have available?
//Doing this so I don't have to keep typing the days of the week
$days = ['Monday','Tuesday','Wednesday','Thursday','Friday','Saturday','Sunday'];
?>
<table class="table">
	<thead>
		<?php
		//Setup the column headers
		foreach($days as $day){ ?>
			<th><?=$day?></th>
		<?php } ?>
	</thead>
	<tbody>
		<tr>
		<?php
		//do the rows and get the count
		foreach ($days as $day) { ?>
			<td><?php echo getCalendarDay($day,$spaces);?></td>
		<?php } ?>
	</tr>
	</tbody>
</table>