use Joomla\CMS\Factory;

$app   = Factory::getApplication();
$db = Factory::getContainer()->get('DatabaseDriver');
// Get query 1
$query = $db->getQuery(true);
// Select some articles with id 5, 8 and 10. Specify this your articles ids.
$query->select('*')->from('#__content')->whereIn('id', [5,8,10]);
$result1 = $db->setQuery($query)->loadAssocList();
// check the result - articles list
// We got an array with 3 articles. ok.
dump($query, $result1);

// Do the same for another articles list
$query = $db->getQuery()->clear();
// or
$query = $db->getQuery(true);
// or
$query->clear(); // We try to save memory and use existing $db
// Fetch 2 another articles
$query->select('*')->from('#__content')->whereIn('id', [1,2]);
$result2 = $db->setQuery($query)->loadAssocList();
// All is fine. We got an array with 2 articles
dump($query, $result2);

// Get query 1
$query = $db->getQuery(true);
// Select one user with email.
$query->select('*')->from('#__users')->whereIn('email', [$db->quote('info@web-tolk.ru')]);
$result1 = $db->setQuery($query)->loadAssocList();
// check the result - I expect a list consist of only 1 user with specified email
// But I got a 2 users
dump($query, $result1);

$query = $db->getQuery()->clear();
// or
$query = $db->getQuery(true);
// or
$query->clear(); // We try to save memory and use existing $db
// Try to fetch second user data
$query->select('*')->from('#__users')->whereIn('username', ['test']);
$result2 = $db->setQuery($query)->loadAssocList();
// I got a 2 users list, but only 1 user expected.
dump($query, $result2);

$query = "SELECT * FROM #__users WHERE email IN(".$db->quote('info@web-tolk.ru').")";

$query = "SELECT * FROM #__users WHERE username IN(".$db->quote('test').")";