根据带有 unix 时间戳的月份和年份选择总和

Question

I am trying to sum all the values in a column for month 10 which is october, but i seem to have unix timestamp

i tried the following but the value remains 0

<?php 
echo $this->db->select('(SELECT SUM(amount_paid) FROM invoice WHERE MONTH (  `creation_timestamp` ) = 10) AS invoice');

$query = $this->db->get('invoice'); 
?>

..

Schema

CREATE TABLE `invoice`(
    `invoice_id` int(11) NOT NULL AUTO_INCREMENT,
    `student_id` int(11) NOT NULL,
    `title` longtext COLLATE utf8_unicode_ci NOT NULL,
    `description` longtext COLLATE utf8_unicode_ci NOT NULL,
    `amount` int(11) NOT NULL,
    `amount_paid` longtext COLLATE utf8_unicode_ci NOT NULL,
    `due` longtext COLLATE utf8_unicode_ci NOT NULL,
    `creation_timestamp` int(11) NOT NULL,
    `payment_timestamp` longtext COLLATE utf8_unicode_ci NOT NULL,
     `payment_method` longtext COLLATE utf8_unicode_ci NOT NULL,
    `payment_details` longtext COLLATE utf8_unicode_ci NOT NULL,
    `status` longtext COLLATE utf8_unicode_ci NOT NULL COMMENT 'paid or unpaid',
    PRIMARY KEY (`invoice_id`)
) ENGINE=MyISAM AUTO_INCREMENT=73 DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci

Answer 1

give this a shot as we are looking for the sum for October 2015 (I think)

SELECT UNIX_TIMESTAMP('2015-10-01'); -- '1443672000'
SELECT UNIX_TIMESTAMP('2015-10-31 23:59:59'); -- 1446350399
SELECT UNIX_TIMESTAMP('2015-11-01'); -- '1446350400'

Note the above values

drop table invoice2;
create table invoice2
(   id int auto_increment primary key,
    amount decimal(12,2) not null,
    ts int(11) not null -- from unix timestamp
);

-- truncate table invoice2;
insert invoice2(amount,ts) values 
(10,unix_timestamp('2015-10-01')),
(10,unix_timestamp('2015-10-01')),
(3310,unix_timestamp('2015-11-01')),
(3310,unix_timestamp('2015-11-01')),
(44410,unix_timestamp('2016-01-01')),
(5510,unix_timestamp('2016-02-01')),
(6610,unix_timestamp('2016-02-01'));

So you want something in the following flavor for October 2015 amounts:

select sum(amount) as theSum 
from invoice2 
where month(from_unixtime(ts))=10  
and year(from_unixtime(ts))=2015;
+--------+
| theSum |
+--------+
|  20.00 |
+--------+

---

the function of interest is get_sum()

Codeigniter Model

 <?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
 class department_model extends CI_Model{

 function __construct()
 {
      // Call the Model constructor
      parent::__construct();
 }

 //read the department list from db
 function get_department_list()
 {
      $sql = 'select var_dept_name, var_emp_name from tbl_dept, tbl_emp where tbl_dept.int_hod = tbl_emp.int_id';
      $query = $this->db->query($sql);
      $result = $query->result();
      return $result;
 }

 // get the sum of amount based on parameters month and year passed
 function get_sum($month,$year) 
 {    $myQuery="select sum(amount) as theSum from invoice2 where month(from_unixtime(ts))=$month  
                and year(from_unixtime(ts))=$year";
      $query = $this->db->query($myQuery);

      $result = $query->result();
      return $result;
 }

}

Answer 2

There is some problems in your query and code as well. when you execute your query directly on database it is giving error. Also for custom queries we have to use $this->db->query() function in CI. Below is the correct query code snippet.

<?php 
   echo $this->db
             ->query('SELECT SUM(amount_paid) AS invoice FROM invoice WHERE MONTH (  `creation_timestamp` ) = 10 ')
             ->row()->invoice;
?>