Work with databases (DB)

<?php

// Connect to the database
$dbh = new PDO("sqlite::memory:");

// A small piece of the "world" database
$dbh->exec("
    CREATE TABLE countrylanguage (
        CountryCode TEXT, Language TEXT, Percentage REAL)");
$dbh->exec("
    INSERT INTO countrylanguage VALUES
        ('RUS', 'Russian', 86.6),
        ('RUS', 'Tatar', 3.2),
        ('RUS', 'Ukrainian', 0.3)");

// SQL query execution
$stmt = $dbh->prepare("
    SELECT
        Language, Percentage
    FROM countrylanguage
    WHERE 
        CountryCode = ? AND
        Percentage > ?");
$stmt->execute(["RUS"0.5]);

while ($row = $stmt->fetch(PDO::FETCH_LAZY)) {
    echo $row['Language'] . ": " . $row['Percentage'], "\n";
}

$dbh = null