// Created on savesnippets.com · https://savesnippets.com/4ggNVomJpBq3OY
<?php
function upsert(PDO $db, string $table, array $row, array $updateCols): bool {
    $cols   = array_keys($row);
    $colSql = '`' . implode('`,`', $cols) . '`';
    $phSql  = implode(',', array_fill(0, count($cols), '?'));
    $updSql = implode(',', array_map(fn($c) => "`$c`=VALUES(`$c`)", $updateCols));

    $sql = "INSERT INTO `$table` ($colSql) VALUES ($phSql) ON DUPLICATE KEY UPDATE $updSql";
    $stmt = $db->prepare($sql);
    $stmt->execute(array_values($row));
    // MySQL: rowCount = 1 for insert, 2 for update, 0 for no-op
    return $stmt->rowCount() === 1;
}

upsert($db, 'page_views', ['url'=>'/about','views'=>1], ['views']);