Update using WHERE

This code worked.
Result: UPDATE `test` SET `activity_id` = NULL WHERE `activity_id` = 100

Model:

PHP Code:

<?php
namespace App\Models;
use CodeIgniter\Model;

class TestModel extends Model
{
    protected $table         = 'test';
    protected $allowedFields = ['activity_id'];

    public function set_activity_id_null($activity_id = false)
    {
        if ($activity_id !== false) {
            $this->where('activity_id', $activity_id)
                ->set('activity_id', null)
                ->update();

            return true;
        }

        return false;
    }
} 


Controller:

PHP Code:

<?php
namespace App\Controllers;

class Home extends BaseController
{
    public function index()
    {
        $model = new \App\Models\TestModel();
        $model->set_activity_id_null(100);
        echo $model->getLastQuery();
    }
} 


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