$host = '127.0.0.1';
$db   = 'test';
$user = 'root';
$pass = '';
$charset = 'utf8';

$dsn = "mysql:host=$host;dbname=$db;charset=$charset";
$opt = [
    PDO::ATTR_ERRMODE            => PDO::ERRMODE_EXCEPTION,
    PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC,
    PDO::ATTR_EMULATE_PREPARES   => false,
];
$pdo = new PDO($dsn, $user, $pass, $opt);

$stmt = $pdo->query('SELECT name FROM users');
while ($row = $stmt->fetch())
{
    echo $row['name'] . "n";
}

$sql = "SELECT * FROM users WHERE email = '$email' AND status='$status'";

$sql = 'SELECT * FROM users WHERE email = ? AND status=?';

$sql = 'SELECT * FROM users WHERE email = :email AND status=:status';

$stmt = $pdo->prepare('SELECT * FROM users WHERE email = ? AND status=?');
$stmt->execute([$email, $status]);
$user = $stmt->fetch();
// o
$stmt = $pdo->prepare('SELECT * FROM users WHERE email = :email AND status=:status');
$stmt->execute(['email' => $email, 'status' => $status]);
$user = $stmt->fetch();

$data = [
    1 => 1000,
    5 =>  300,
    9 =>  200,
];
$stmt = $pdo->prepare('UPDATE users SET bonus = bonus + ? WHERE id = ?');
foreach ($data as $id => $bonus)
{
    $stmt->execute([$bonus, $id]);
}

$sql = "UPDATE users SET name = ? WHERE id = ?";
$pdo->prepare($sql)->execute([$name, $id]);

$stmt = $pdo->prepare("DELETE FROM goods WHERE category = ?");
$stmt->execute([$cat]);
$deleted = $stmt->rowCount();

$stmt = $pdo->query('SELECT name FROM users');
foreach ($stmt as $row)
{
    echo $row['name'] . "n";
}

$row = $stmt->fetch(PDO::FETCH_ASSOC);

$news = $pdo->query('SELECT * FROM news')->fetchAll(PDO::FETCH_CLASS, 'News');

create table typetest (string varchar(255), `int` int, `float` float, `null` int);
insert into typetest values('foo',1,1.1,NULL);

array(4) {
  ["string"] => string(3) "foo"
  ["int"]    => int(1)
  ["float"]  => float(1.1)
  ["null"]   => NULL
}

$pdo->setAttribute(PDO::ATTR_STRINGIFY_FETCHES, true);

// Obteniendo el nombre basado en el id
$stmt = $pdo->prepare("SELECT name FROM table WHERE id=?");
$stmt->execute([$id]);
$name = $stmt->fetchColumn();

// Obteniendo el número de filas en la tabla usando el encadenamiento de métodos
$count = $pdo->query("SELECT count(*) FROM table")->fetchColumn();

$data = $pdo->query('SELECT name FROM users')->fetchAll();
var_export($data);
/* array (
  0 => array('John'),
  1 => array('Mike'),
  2 => array('Mary'),
  3 => array('Kathy'),
)*/

$data = $pdo->query('SELECT name FROM users')->fetchAll(PDO::FETCH_COLUMN);
/* array (
  0 => 'John',
  1 => 'Mike',
  2 => 'Mary',
)*/

$data = $pdo->query('SELECT id, name FROM users')->fetchAll(PDO::FETCH_KEY_PAIR);
/* array (
  104 => 'John',
  110 => 'Mike',
  120 => 'Mary',
)*/

$data = $pdo->query('SELECT * FROM users')->fetchAll(PDO::FETCH_UNIQUE);
/* array (
  104 => array (
    'name' => 'John',
    'car' => 'Toyota',
  ),
  110 => array (
    'name' => 'Mike',
    'car' => 'Ford',
  ),
  120 => array (
    'name' => 'Mary',
    'car' => 'Mazda',
  ),
)*/

$data = $pdo->query('SELECT sex, name, car FROM users')->fetchAll(PDO::FETCH_GROUP);
/* array (
  'male' => array (
    0 => array (
      'name' => 'John',
      'car' => 'Toyota',
    ),
    1 => array (
      'name' => 'Mike',
      'car' => 'Ford',
    ),
  ),
  'female' => array (
    0 => array (
      'name' => 'Mary',
      'car' => 'Mazda',
    ),
    1 => array (
      'name' => 'Kathy',
      'car' => 'Mazda',
    ),
  ),
)*/

$stmt = $pdo->prepare("SELECT 1 FROM users WHERE name=?");
$stmt->execute([$name]);
$userExists = $stmt->fetchColumn();

$data = $pdo->query("SELECT * FROM table")->fetchAll();
if ($data) {
    // ¡Tiene los datos, no necesita para nada usar rowCount()!
}

$count = $pdo->query("SELECT count(1) FROM t")->fetchColumn();

$stmt = $pdo->prepare("SELECT * FROM table WHERE name LIKE '%?%'");

$search = "%$search%";
$stmt  = $pdo->prepare("SELECT * FROM table WHERE name LIKE ?");
$stmt->execute([$search]);
$data = $stmt->fetchAll();

$arr = [1,2,3];
$in  = str_repeat('?,', count($arr) - 1) . '?';
$sql = "SELECT * FROM table WHERE column IN ($in)";
$stm = $db->prepare($sql);
$stm->execute($arr);
$data = $stm->fetchAll();

$arr = [1,2,3];
$in  = str_repeat('?,', count($arr) - 1) . '?';
$sql = "SELECT * FROM table WHERE foo=? AND column IN ($in) AND bar=? AND baz=?";
$stm = $db->prepare($sql);
$params = array_merge([$foo], $arr, [$bar, $baz]);
$stm->execute($params);
$data = $stm->fetchAll();

// other parameters that are going into query
$params = ["foo" => "foo", "bar" => "bar"];

$ids = [1,2,3];
$in = "";
foreach ($ids as $i => $item)
{
    $key = ":id".$i;
    $in .= "$key,";
    $in_params[$key] = $item; // collecting values into key-value array
}
$in = rtrim($in,","); // :id0,:id1,:id2

$sql = "SELECT * FROM table WHERE foo=:foo AND id IN ($in) AND bar=:bar";
$stm = $db->prepare($sql);
$stm->execute(array_merge($params,$in_params)); // just merge two arrays
$data = $stm->fetchAll();