PHP 함수에서 데이터베이스 쿼리 성능을 최적화하는 방법은 무엇입니까?

$cache = new Cache();
$key = 'results';
if ($cache->has($key)) {
    $results = $cache->get($key);
} else {
    $results = $db->query('SELECT * FROM users');
    $cache->set($key, $results);
}

$db->query('CREATE INDEX idx_name ON users (name)');

$db->query('UPDATE users SET name = :name WHERE id = :id', [
    ':name' => $name, ':id' => $id
]);

$db->query('SELECT * FROM users LIMIT 10 OFFSET 0');

$db->query('EXPLAIN SELECT * FROM users WHERE name LIKE "%John%"');

$stmt = $db->prepare('SELECT * FROM users WHERE name = ?');
$stmt->execute([$name]);

<?php
// 缓存结果
$cache = new Cache();
$key = 'popular_products';
if ($cache->has($key)) {
    $products = $cache->get($key);
} else {
    // 使用适当的查询类型
    $stmt = $db->prepare('SELECT * FROM products ORDER BY views DESC LIMIT 10');
    $stmt->execute();
    $products = $stmt->fetchAll();
    $cache->set($key, $products);
}