How to use php with mysql?

As @vaultdweller123 observed, one side handles application logic and the other stores data. Practically, the “link” is a PHP database driver/extension that opens a connection, sends SQL, and returns results. Modern, supported drivers are PDO and mysqli; the old mysql_* extension is removed from recent PHP releases, so use a supported API and prepared statements for safety.

Typical workflow (concise):

• enable the chosen extension in PHP (check phpinfo()),
• open a connection with host, dbname, user, password and set the character set,
• prepare statements with placeholders, bind parameters and execute,
• fetch results and close the connection,
• handle errors and use transactions for multi-step updates.

A minimal PDO example:

$dsn = 'mysql:host=localhost;dbname=testdb;charset=utf8mb4';
$options = [PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION];
$pdo = new PDO($dsn, 'dbuser', 'dbpass', $options);
$stmt = $pdo->prepare('SELECT id, name FROM users WHERE email = :email');
$stmt->execute([':email' => $email]);
$row = $stmt->fetch(PDO::FETCH_ASSOC);

Troubleshooting and cautions:

• If the extension is missing, verify PHP version and php.ini (or check phpinfo()).
• Connection failures often come from wrong host/port, socket vs TCP issues, firewall, or wrong credentials.
• Avoid embedding DB credentials in webroot; use environment variables or protected config files and a least-privilege DB user (not root).
• Always set the connection charset (utf8mb4) to avoid encoding issues and reduce injection risks.

Helpful, current references:

• PDO overview and prepared statements: https://www.php.net/manual/en/book.pdo.php
• mysqli quickstart: https://www.php.net/manual/en/mysqli.quickstart.overview.php
• ext/mysql removal / migration notes: https://www.php.net/manual/en/migration70.deprecated.php
• SQL injection prevention guidance: https://owasp.org/www-community/attacks/SQL_Injection

This complements the earlier replies by focusing on modern, secure practice rather than older examples or generic search tips noted by @WillGresham and the manual link posted by @almostbob.