Database LIKE condition

The like condition syntax is:

$query->condition('field_name', "%" . $query->escapeLike("The string") . "%", 'LIKE');

Example:

    $con = \Drupal\Core\Database\Database::getConnection();

    $query = $con->select('table_name', 't')

        ->fields('t', ['field_1', 'field_2']);

    $query->condition('field_1', "%" . $query->escapeLike($string) . "%", 'LIKE');

    $result = $query->execute()->fetchAll();