timetable for scheduled subjects - php

Question

i got it right though my problem now is how can i put a style on the table row that has the data inside it and much better if i can put rowspan to it so that it will look like one table row.
here is the output:
and here is my code:
<?php
$db = new mysqli("localhost", "root", "", "bsu_db");
if($db->connect_errno > 0){
die('Unable to connect to database [' . $db->connect_error . ']');
}
$times = ["7:00:00", "7:30:00", "8:00:00", "8:30:00", "9:00:00", "9:30:00", "10:00:00", "10:30:00", "11:00:00", "11:30:00", "12:00:00"];
$days = ["Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"];
$SubjDay = array();
$sqlSubjDay = "SELECT * FROM subject_day_tbl";
$qrySubjDay = $db->query($sqlSubjDay);
while($rowSubjDay = $qrySubjDay->fetch_assoc()){
//array_push($SubjDay, $rowSubjDay['sub_day'], $rowSubjDay['start_time'], $rowSubjDay['end_time']);
$SubjDay[] = $rowSubjDay;
}
json_encode($SubjDay);
?>
<table class="table table-bordered table-condensed">
<thead>
<tr>
<th></th>
<?php
foreach ($days as $day ) {
echo "<th>$day</th>";
}
?>
</tr>
</thead>
<tbody>
<?php
foreach ($times as $time) {
?>
<tr>
<td><?php echo $time; ?></td>
<?php
foreach ($days as $day) {
echo "<td>";
foreach($SubjDay as $sd){
if($day == $sd['sub_day'] && strtotime($time) >= strtotime($sd['start_time']) && strtotime($time) <= strtotime($sd['end_time'])){
echo $sd['sub_day'] , " " , $sd['start_time'] , " - " , $sd['end_time'];
}
}
echo "</td>";
}
?>
</tr>
<?php
}
?>
</tbody>
</table>