$("#change_student").prepend( $('<option value="new">'+new_student+'</option>') );
$grouped = [];
foreach ($date as $d) {
$parts = explode('-', $d);
$grouped[$parts[0]][intval($parts[1])][] = intval($parts[2]);
}
$row[8] = "<form action='' method='post'><input type='hidden' name='product_option_id' value='".$row['product_option_id']."'><input type='submit' value='Удалить'></form>";
SELECT *
FROM oc_product_option
WHERE product_id IN (
SELECT product_id
FROM oc_product_option
GROUP BY product_id
HAVING count(product_id) > 1
)