class DatabaseTestForm

class DatabaseTestForm extends FormBase {
    
    /**
     * {@inheritdoc}
     */
    public function getFormId() {
        return 'database_test_theme_tablesort';
    }
    
    /**
     * {@inheritdoc}
     */
    public function buildForm(array $form, FormStateInterface $form_state) {
        $header = [
            'username' => [
                'data' => t('Username'),
                'field' => 'u.name',
            ],
            'status' => [
                'data' => t('Status'),
                'field' => 'u.status',
            ],
        ];
        $query = Database::getConnection()->select('users_field_data', 'u');
        $query->condition('u.uid', 0, '<>');
        $query->condition('u.default_langcode', 1);
        $count_query = clone $query;
        $count_query->addExpression('COUNT([u].[uid])');
        $query = $query->extend(PagerSelectExtender::class)
            ->extend(TableSortExtender::class);
        $query->fields('u', [
            'uid',
        ])
            ->limit(50)
            ->orderByHeader($header)
            ->setCountQuery($count_query);
        $uids = $query->execute()
            ->fetchCol();
        $options = [];
        foreach (User::loadMultiple($uids) as $account) {
            $options[$account->id()] = [
                'title' => [
                    'data' => [
                        '#title' => $account->getAccountName(),
                    ],
                ],
                'username' => $account->getAccountName(),
                'status' => $account->isActive() ? t('active') : t('blocked'),
            ];
        }
        $form['accounts'] = [
            '#type' => 'tableselect',
            '#header' => $header,
            '#options' => $options,
            '#empty' => t('No people available.'),
        ];
        return $form;
    }
    
    /**
     * {@inheritdoc}
     */
    public function submitForm(array &$form, FormStateInterface $form_state) {
    }

}