select max codeigniter - php

Question

Im trying to get an max value with codeigniter from an table but it isnt working. This is the error i get:
Severity: 4096
Message: Object of class CI_DB_mysql_result could not be converted to
string
Filename: database/DB_active_rec.php
Line Number: 427
This is my function:
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;
}
What im trying to do is as followed:
Select the highest id where bedrijf_id = $bedrijf_id from rapporten.
Select the periode_nummer from statistieken_onderhoud where rapporten_id = the highest id i got from step 1.
Add 1 to the periode_nummer i got from step 2 and return that number.
Thanks in forward for your help!

Answer 1

Try
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;
}

Answer 2

Try this:
$this->db->select_max('display_sequence');
$this->db->from('acl_menu');
$query = $this->db->get();
$r=$query->result();
Display Sequence is your column name & acl_menu is your table name.

Answer 3

You can't use an object as a string. Use this:
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');
// fetch first row in object
$result = $query->row();
$data = $result + 1;
return $data;
}

Answer 4

$this->db->select_max('id', 'max_id');
$query = $this->db->get('video_processing');
return $query->row();
try the above:

Answer 5

I think the $query variable is holding a mysql result resource and it cannot be used as a String or in this case an Integer.
You could try this way:
$data = mysql_result($query,0) + 1;

Answer 6

Shortest:
$this->db->select_max('id', 'max_id')->get('video_processing')->row();