php - 比较两个时间戳 Codeigniter

Question

我正在尝试计算用户在 Codeigniter 中收到的通知数量。我正在比较每个用户行中保存的时间戳(记录他们上次检查通知页面的时间)和为每个通知添加的时间。但是我收到数据库错误:

A Database Error Occurred

Error Number: 1064

You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '10:17:00' at line 5

SELECT * FROM (`notifications`) WHERE `user_id` = '1' AND `instigator_id` != '1' AND added <= 2014-11-04 10:17:00

文件名:/Users/true/Documents/Site/models/private/notifications_model.php

行号:152

通知 Controller 看起来像这样

$data["user"] = $CI->Profile_model->get_public_profile_id($logged_user);
$count = $CI->notifications_model->get_notifications_count($data["user"][0]["notes_check"]);

型号:

public function get_notifications_count($time){


    $this->db->from($this->notifications_table);
    $this->db->where('user_id', $this->session->userdata("id", 0)); 
    $this->db->where('instigator_id !=', $this->session->userdata("id", 0));
    $this->db->where('added <= '.$time, '', false); 
    $query = $this->db->get();
    $results = $query->result_array();

    return count($results);
}

Answer 1

您的日期/时间值是字符串。由于它们周围没有 '-引号，MySQL 会看到:

added <= 2014-11-04 10:17:00
         ^^^^^^^^^^---mathematical subtraction = 1999
                   ^^^^^^^^^--illegal unknown field/table name

应该是

added <= '2014-11-04 10:17:00'

注意引号。