试试这个：

public function search()
{
    $query = $this->input->get('q');

    // Search the news table
    $this->db->select('*');
    $this->db->from('news');
    $this->db->like('title', $query);
    $this->db->or_like('content', $query);
    $news_results = $this->db->get()->result_array();

    // Search the events table
    $this->db->select('*');
    $this->db->from('events');
    $this->db->like('title', $query);
    $this->db->or_like('description', $query);
    $events_results = $this->db->get()->result_array();

    // Search the notices table
    $this->db->select('*');
    $this->db->from('notices');
    $this->db->like('title', $query);
    $this->db->or_like('content', $query);
    $notices_results = $this->db->get()->result_array();

    // Combine the results and pass them to the view
    $data = array(
        'news_results' => $news_results,
        'events_results' => $events_results,
        'notices_results' => $notices_results,
    );
    $this->load->view('search_results', $data);
}

我认为您必须更详细地解释您希望如何搜索以及您希望如何显示结果。