set_charset(‘utf8mb4’);<\/p>\n
\/\/ Check for database connection errors
\nif ($conn->connect_error) {
\n die(‘Connection failed: ‘ . htmlspecialchars($conn->connect_error));
\n}<\/p>\n
$result = null;<\/p>\n
if ($_SERVER[‘REQUEST_METHOD’] == ‘POST’) {
\n $grade = $conn->real_escape_string($_POST[‘grade’]);
\n $subject = $conn->real_escape_string($_POST[‘subject’]);
\n $chapter = $conn->real_escape_string($_POST[‘chapter’]);
\n $section = $conn->real_escape_string($_POST[‘section’]);<\/p>\n
$sql = “SELECT * FROM topics WHERE grade=’$grade’ AND subject=’$subject’ AND chapter=’$chapter’ AND section=’$section'”;
\n $result = $conn->query($sql);<\/p>\n
\/\/ Check for query execution errors
\n if (!$result) {
\n die(‘Query failed: ‘ . htmlspecialchars($conn->error));
\n }
\n} else {
\n \/\/ Fetch the last 20 posts
\n $sql = ‘SELECT * FROM topics ORDER BY created_at DESC LIMIT 20’;
\n $result = $conn->query($sql);<\/p>\n
\/\/ Check for query execution errors
\n if (!$result) {
\n die(‘Query failed: ‘ . htmlspecialchars($conn->error));
\n }
\n}
\n?><\/p>\n
\n
\n