选择max codeigniter

Question

我试图从表中获取codeigniter的最大值,但它不起作用.这是我得到的错误:

严重程度:4096

消息:类CI_DB_mysql_result的对象无法转换为字符串

文件名:database/DB_active_rec.php

行号:427

这是我的功能:

public function getPeriodeNummer($bedrijf_id) {
    $this->db->select_max('id');
    $this->db->where('bedrijf_id', $bedrijf_id);
    $result = $this->db->get('rapporten');

    $this->db->select('periode_nummer');
    $this->db->where('rapporten_id', $result);
    $query = $this->db->get('statistieken_onderhoud');

    $data = $query + 1;

    return $data;
}

我想要做的是如下:

1. 选择最高的idwhere bedrijf_id= $bedrijf_idfrom rapporten.
2. 选择periode_nummerfrom = statistieken_onderhoudwhere rapporten_id= id我从步骤1获得的最高值.
3. 添加1到periode_nummer我从步骤2得到的return那个号码.

在此感谢您的帮助!

Answer 1

尝试

public function getPeriodeNummer($bedrijf_id) {
    $this->db->select_max('id');
    $this->db->where('bedrijf_id', $bedrijf_id);
    $res1 = $this->db->get('rapporten');

    if ($res1->num_rows() > 0)
    {
        $res2 = $res1->result_array();
        $result = $res2[0]['id'];

        $this->db->select('periode_nummer');
        $this->db->where('rapporten_id', $result);
        $query = $this->db->get('statistieken_onderhoud');

        if ($query->num_rows() > 0)
        {
            $row = $query->result_array();
            $data['query'] = 1 + $row[0]['periode_nummer'];
        }

        return $data['query'];
    }

    return NULL;
}