MySQL Intro

PHP talks to MySQL through two main extensions: mysqli and PDO. Both ship with PHP. For new code, prefer PDO — it's portable across databases.

The choice

PDO — the modern default

$pdo = new PDO(
    'mysql:host=localhost;dbname=shop;charset=utf8mb4',
    'user',
    'pass',
    [
        PDO::ATTR_ERRMODE             => PDO::ERRMODE_EXCEPTION,
        PDO::ATTR_DEFAULT_FETCH_MODE  => PDO::FETCH_ASSOC,
        PDO::ATTR_EMULATE_PREPARES    => false,
    ],
);

foreach ($pdo->query('SELECT id, name FROM customers') as $row) {
    echo $row['name'], PHP_EOL;
}

mysqli — for legacy code or one-off scripts

$mysqli = new mysqli('localhost', 'user', 'pass', 'shop');
$mysqli->set_charset('utf8mb4');

$result = $mysqli->query('SELECT id, name FROM customers');
while ($row = $result->fetch_assoc()) {
    echo $row['name'], PHP_EOL;
}

Connection string essentials

• host — usually localhost or an IP/hostname.
• dbname — which database to use.
• charset=utf8mb4 — the only sane choice in 2026. Plain utf8 in MySQL is a 3-byte subset.
• Production: never commit credentials. Read from env vars / a secrets manager.

What to read next

The lessons in this section walk you through connecting, creating tables, inserting/selecting/updating/deleting data, and prepared statements. Each uses PDO; mysqli equivalents are flagged in the references.

Example

<?php
// PHP talks to MySQL via mysqli or PDO.
// PDO is generally preferred for new code.
echo 'See the connect lesson for a working example.';

Exercise

Test yourself