PHP - Insert multiple rows into MySQL table using a single query statement. Example based on code from https://phpacademy.org/topics/how-to-insert-multiple-rows-in-mysql-in-one-query-using-pdo-from-a-form/34096

php-mysql-add-insert-multiple-rows-single-query.php

<?php
// https://phpacademy.org/topics/how-to-insert-multiple-rows-in-mysql-in-one-query-using-pdo-from-a-form/34096
function placeholder( $text, $count = 0, $separator = ',' ) {
	$result = array();

	if ($count > 0) {
		for ($x = 0; $x < $count; $x++) {
			$result[] = $text;
		}
	}

	return implode( $separator, $result );
}

$pdo = new PDO("mysql:host=$dbhost;dbname=$dbname",$dbuser,$dbpass);

$datafields = array( 'student_name' => '', 'roll_no' => '', 'subject' => '' );

$data[] = array( 'student_name' => 'John Doe', 'roll_no' => 'CC0801', 'subject' => 'Computer Networks' );
$data[] = array( 'student_name' => 'Jane Doe', 'roll_no' => 'CC0802', 'subject' => 'Computer Networks' );
$data[] = array( 'student_name' => 'Summer Doe', 'roll_no' => 'CC0803', 'subject' => 'Computer Networks' );

$pdo->beginTransaction(); // Speed up your inserts

$insertvalues = array();

foreach ($data as $d) {
	$questionmarks[] = '(' . placeholder( '?', sizeof($d)) . ')';
	$insertvalues = array_merge( $insertvalues, array_values($d) );
}

$sql = "INSERT INTO table (" . implode( ',', array_keys( $datafields ) ) . ") VALUES " . implode( ',', $questionmarks);

$statement = $pdo->prepare($sql);

try {
	$statement->execute($insertvalues);
} catch(PDOException $e) {
	echo $e->getMessage();
}
$pdo->commit();