PHP: List multiple record grouped by date - php

Question

I'm trying to list multiple record from MySQL Database using PHP but when grouping it returns only one record from database, below is my PHP code I'm using.
<?php
include "connection.php";
$query = "select * from lectureupload GROUP BY submittedOn";
$result=mysqli_query($conn, $query);
while ($row = mysqli_fetch_array($result)) {
echo '<table class="table">';
echo '<thead>';
echo '<td><strong>ID</strong></td>';
echo '<td><strong>Title</strong></td>';
echo '<td><strong>Semester</strong></td>';
echo '<td><strong>Teacher</strong></td>';
echo '<td><strong>Lecture Link</strong></td>';
echo '<td><strong>Submitted On</strong></td>';
echo '</thead>';
echo '<div class="section-header">';
echo '<br>';
echo '<h3>'.$row['submittedOn'].'</h3>';
echo '</div>';
echo '<tr >';
echo '<td>'.$row['id'].'</td>';
echo '<td>'.$row['title'].'</td>';
echo '<td>'.$row['semester'].'</td>';
echo '<td>'.$row['teacherName'].'</td>';
echo '<td>'.$row['lectureLink'].'</td>';
echo '<td>'.$row['submittedOn'].'</td>';
echo '</tr>';
echo '</table>';
}
mysqli_close($conn);
?>
The current Result it gives me is somewhat like that,
My Database table is this.
Solution to this problem will be highly appreciated.
Regards.

Answer 1

You can't use GROUP BY clause to retrieve all records from that table. GROUP BY will always return one row per GROUP BY CONDITIONAL_COLUMN. I will suggest you below modification:
<?php
include "connection.php";
//ORDER BY submittedOn will make sure the records retrieved in ordered as per submittedOn.
$query = "select * from lectureupload ORDER BY submittedOn";
$result = mysqli_query($conn, $query);
$submitted_on_keys = array();
while ($row = mysqli_fetch_array($result)) {
if (!in_array($row['submittedOn'], $submitted_on_keys)) {
if (count($submitted_on_keys) > 0) {
//It means we have already created <table> which needs to be closed.
echo '</table>';
}
$submitted_on_keys[] = $row['submittedOn'];
echo '<table class="table">';
echo '<thead>';
echo '<td><strong>ID</strong></td>';
echo '<td><strong>Title</strong></td>';
echo '<td><strong>Semester</strong></td>';
echo '<td><strong>Teacher</strong></td>';
echo '<td><strong>Lecture Link</strong></td>';
echo '<td><strong>Submitted On</strong></td>';
echo '</thead>';
echo '<div class="section-header">';
echo '<br>';
echo '<h3>' . $row['submittedOn'] . '</h3>';
echo '</div>';
}
echo '<tr >';
echo '<td>' . $row['id'] . '</td>';
echo '<td>' . $row['title'] . '</td>';
echo '<td>' . $row['semester'] . '</td>';
echo '<td>' . $row['teacherName'] . '</td>';
echo '<td>' . $row['lectureLink'] . '</td>';
echo '<td>' . $row['submittedOn'] . '</td>';
echo '</tr>';
}
if (count($submitted_on_keys) > 0) {
//There is last <table> which needs to be closed.
echo '</table>';
}
mysqli_close($conn);
?>

Answer 2

You should group it in your PHP code rather than your SQL.
Something like this:
$lectures = [];
$result = mysqli_query($conn, "select * from lectureupload");
while ($row = mysqli_fetch_array($result)) {
$lectures[$row['submittedOn']][] = $row;
}
foreach ($lectures as $submittedOn => $rows) {
echo '<table class="table">';
echo '<thead>';
echo '<td><strong>ID</strong></td>';
echo '<td><strong>Title</strong></td>';
echo '<td><strong>Semester</strong></td>';
echo '<td><strong>Teacher</strong></td>';
echo '<td><strong>Lecture Link</strong></td>';
echo '<td><strong>Submitted On</strong></td>';
echo '</thead>';
echo '<div class="section-header">';
echo '<br>';
echo '<h3>'.$submittedOn.'</h3>';
echo '</div>';
foreach ($rows as $row) {
echo '<tr >';
echo '<td>'.$row['id'].'</td>';
echo '<td>'.$row['title'].'</td>';
echo '<td>'.$row['semester'].'</td>';
echo '<td>'.$row['teacherName'].'</td>';
echo '<td>'.$row['lectureLink'].'</td>';
echo '<td>'.$row['submittedOn'].'</td>';
echo '</tr>';
}
echo '</table>';
}