Mysql : Get segmented records between multiple date range

Question

Table structure and sample data

CREATE TABLE IF NOT EXISTS `orders` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `customer_id` int(11) NOT NULL,
  `restaurant_id` int(11) NOT NULL,
  `bill_id` int(11) NOT NULL,
  `source_id` int(1) NOT NULL,
  `order_medium_id` int(11) NOT NULL,
  `purchase_method` varchar(255) NOT NULL,
  `totalamount` int(11) NOT NULL,
  `delivery_charg` int(11) NOT NULL,
  `discount` int(11) NOT NULL,
  `vat` int(11) NOT NULL,
  `total_price` int(11) NOT NULL DEFAULT '0',
  `date_created` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
  PRIMARY KEY (`id`),
  KEY `customer_id` (`customer_id`),
  KEY `source_id` (`source_id`),
  KEY `restaurant_id` (`restaurant_id`),
  KEY `bill_id` (`bill_id`)
) ENGINE=InnoDB  DEFAULT CHARSET=latin1 AUTO_INCREMENT=22 ;

--
-- Dumping data for table `orders`
--

INSERT INTO `orders` (`id`, `customer_id`, `restaurant_id`, `bill_id`, `source_id`, `order_medium_id`, `purchase_method`, `totalamount`, `delivery_charg`, `discount`, `vat`, `total_price`, `date_created`) VALUES
(1, 1, 1, 1, 1, 0, 'cash', 1600, 0, 0, 0, 1600, '2016-05-29 13:05:40'),
(2, 1, 1, 2, 2, 1, 'cash', 1820, 0, 0, 0, 1820, '2016-06-27 07:21:25'),
(4, 1, 1, 3, 3, 0, 'cash', 1770, 0, 0, 0, 1770, '2016-05-31 13:05:56'),
(5, 1, 1, 4, 2, 1, 'cash', 1300, 0, 0, 0, 1300, '2016-06-27 07:21:31'),
(6, 1, 1, 5, 1, 0, 'cash', 950, 0, 0, 0, 950, '2016-06-02 13:06:15'),
(7, 1, 1, 6, 1, 0, 'cash', 1640, 0, 0, 0, 1640, '2016-06-03 13:06:24'),
(8, 1, 1, 7, 2, 2, 'cash', 1600, 0, 0, 0, 1600, '2016-06-27 07:21:36'),
(9, 1, 1, 8, 2, 2, 'cash', 1575, 0, 0, 0, 1575, '2016-06-27 07:21:40'),
(10, 1, 1, 9, 3, 0, 'cash', 1125, 0, 0, 0, 1125, '2016-06-06 13:06:48'),
(11, 1, 1, 10, 2, 3, 'cash', 1920, 0, 0, 0, 1920, '2016-06-27 07:21:51');

Requirement :

I want to segment records as per customer as following. 
1. customers who ordered in last 2 week then give ratingflag 5
2. customers who ordered between 2 weeks to 4 week then give ratingflag 3
3. customers who ordered between 4 weeks to 8 week then give ratingflag 2
and so on.

Customer should be unique. We write a query for getting records according to requirement. I don't have so much data in my table, so i made change in condition according to my data.

I tried following . I would appreciate if you could help me with better approach of doing the same :

Query i tried

select customer_id,rating from (select `customer_id`,5 as rating from orders where `restaurant_id` = 1 and  (DATE(`date_created`) between DATE(DATE_SUB(NOW(), INTERVAL 1 DAY)) AND DATE(NOW())) GROUP BY customer_id
UNION ALL
select `customer_id`,4 as rating from orders where `restaurant_id` = 1 and  (DATE(`date_created`) BETWEEN DATE(DATE_SUB(NOW(), INTERVAL 4 DAY)) AND DATE(DATE_SUB(NOW(), INTERVAL 2 DAY))) GROUP BY customer_id
UNION ALL
select `customer_id`,3 as rating from orders where `restaurant_id` = 1 and  (DATE(`date_created`) BETWEEN DATE(DATE_SUB(NOW(), INTERVAL 8 DAY)) AND DATE(DATE_SUB(NOW(), INTERVAL 5 DAY))) GROUP BY customer_id
UNION ALL
select `customer_id`,2 as rating from orders where `restaurant_id` = 1 and  (DATE(`date_created`) BETWEEN DATE(DATE_SUB(NOW(), INTERVAL 20 DAY)) AND DATE(DATE_SUB(NOW(), INTERVAL 9 DAY))) GROUP BY customer_id
UNION ALL
select `customer_id`,1 as rating from orders where `restaurant_id` = 1 and  (DATE(`date_created`) BETWEEN DATE(DATE_SUB(NOW(), INTERVAL 40 DAY)) AND DATE(DATE_SUB(NOW(), INTERVAL 21 DAY))) GROUP BY customer_id) as temp group by customer_id order by rating desc;

Answer 1

Hmmm, I think you just want the date of the most recent order and a big case statement. Something like this:

select o.customer_id,
       (case when max(date_created) >= date_sub(now(), interval 2 week) then 1
             when max(date_created) >= date_sub(now(), interval 4 week) then 2
             when max(date_created) >= date_sub(now(), interval 8 week) then 3
             . . .
        end) as rating
from orders o
group by o.customer_id;

Note that the case evaluates the conditions in order. This is why between is not necessary. The first matching condition ends the processing of the case.