Highlight td elements with events - php

Question

I am generating a calendar via PHP date() function, I also have an events table that has a name and date_start, what I want to do is to highlight the td elements that have events on them and leave the ones without with the basic formatting.
Basically, this is the script that loops the day:
<?php
echo "<tr>";
for ($i = 1; $i < $numDays+1; $i++, $counter++) {
$timeStamp = strtotime ("$year-$month-$i");
if($i == 1){
$firstDay = date ("w", $timeStamp);
for ($j = 0; $j < $firstDay; $j++, $counter++){
//blank space
echo "<td> </td>";
}
}
if($counter % 7 == 0 ){
echo "<tr></tr>";
}
$todayDate = date("Y-m-d");
if (date("Y-m-d", $timeStamp) == $todayDate) {
?>
<td class="today-date"><?php echo $i; ?></td>
<?php
} else {
?>
<td><?php echo $i; ?></td>
<?php
}
}
echo "</tr>";
?>
.today-date is a class to highlight the current day. This is my table columns:
id | name | description | date_start | date_end | time | pastor_id | pastor | category | venue

Answer 1

I would probably put my events into an array with a key for the start date, so you end up with something like:
$events = [
'2017-08-22' => [
'name' => 'Event Title',
],
'2017-08-28' => [
'name' => 'Event Title',
'name' => 'Event Title',
],
];
There are multiple ways of doing this from a DB. Something like this:
$events = [];
while($row = mysql_fetch_assoc($eventQuery))
{
$events[$row['start_date']][] = $row['name'];
}
Then in your loop, you can check the date for an event and put it in:
<td class="<?php echo (array_key_exists(date("Y-m-d", $timeStamp), $events)) ? 'has-event-class' : ''; ?>">
Making database queries for every day in the calendar will be very inefficient compared to pulling all, or even the months'.
I would also be inclined to move this into a function so it's not as long in your loop:
function highlightEventTD($timeStamp, $events)
{
$date = date("Y-m-d", $timeStamp);
return (array_key_exists($date, $events)) ? 'has-event-class' : '';
}
Then in your forloop:
<td class="<?php echo highlightEventTD($timeStamp, $events); ?>">
It also means that if you need to show the name of the event, you can use the same array and a function:
function getEvents($timestamp, $events)
{
$date = date("Y-m-d", $timeStamp);
return (array_key_exists($date, $events)) ? $events[$date] : null;
}

Answer 2

Ok, first of all, PHP7 doesn't like anymore open and close php tag many times... I changed syntax with echo.
So try this :
// here make a SQL query (only one query is enough)
// on your database, for example :
$dates = array();
$q = "SELECT * FROM `events`";
if($res = $pdo->query($q) {
if($res = $res->fetchAll(PDO::FETCH_OBJ)) {
if(sizeof($res) > 0) {
foreach($res as $k => $d) {
$events[$d['date_start']] = $d;
}
}
}
}
echo "<tr>";
for ($i = 1; $i < $numDays + 1; $i++, $counter++) {
$timeStamp = strtotime ("$year-$month-$i");
if($i == 1){
$firstDay = date ("w", $timeStamp);
for ($j = 0; $j < $firstDay; $j++, $counter++) {
echo "<td> </td>"; //blank space
}
}
if($counter % 7 == 0 ) {
echo "<tr></tr>";
}
if (date("Y-m-d", $timeStamp) == date("Y-m-d")) {
$class = "today-date ";
}
if (array_key_exists(date("Y-m-d"), $events)) {
$class .= "event-date ";
}
// 1. solution based on your code
echo "<td class=\"$class\">$i</td>";
// 2. alternative with events in each day :
echo "<td class=\"$class\">";
if(sizeof($eventsOfTheDay = $events[$d['date_start']]) > 0 {
foreach($eventsOfTheDay as $k => $event) {
echo '', $event['name'], '<br>';
}
}
echo "</td>";
}
echo "</tr>";