Mysql – Trouble with a NOT IN query

SELECT DISTINCT d.customer_id, d.date_added FROM `order` d
WHERE d.customer_id NOT IN (
    SELECT DISTINCT i.customer_id 
    FROM `order` i 
    WHERE i.date_added > '2015-02-15 14:00:00'
)
ORDER BY d.date_added DESC;

The above query should return customer_id of customers who have not ordered after 15 Feb 2015 (I think). But very first record is
17168, 2015-08-16 17:36:00

What am I doing wrong?

This below query

SELECT DISTINCT i.customer_id,i.date_added FROM `order` i 
WHERE i.date_added > '2015-02-15 14:00:00' 
ORDER BY i.date_added ASC;

returns expected result i.e. list of customer ids for orders placed after 15 Feb

P.S. customer_id can not be NULL

P.P.S.

mysql> SHOW CREATE TABLE `order`;
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| Table | Create Table                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |
+-------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| order | CREATE TABLE `order` (
  `order_id` int(11) NOT NULL AUTO_INCREMENT,
  `invoice_no` int(11) NOT NULL,
  `invoice_prefix` varchar(26) NOT NULL,
  `store_id` int(11) NOT NULL,
  `store_name` varchar(64) NOT NULL,
  `store_url` varchar(255) NOT NULL,
  `customer_id` int(11) NOT NULL,
  `customer_group_id` int(11) NOT NULL,
  `firstname` varchar(32) NOT NULL,
  `lastname` varchar(32) NOT NULL,
  `email` varchar(96) NOT NULL,
  `telephone` varchar(32) NOT NULL,
  `fax` varchar(32) NOT NULL,
  `custom_field` text NOT NULL,
  `payment_firstname` varchar(32) NOT NULL,
  `payment_lastname` varchar(32) NOT NULL,
  `payment_company` varchar(40) NOT NULL,
  `payment_address_1` varchar(128) NOT NULL,
  `payment_address_2` varchar(128) NOT NULL,
  `payment_city` varchar(128) NOT NULL,
  `payment_postcode` varchar(10) NOT NULL,
  `payment_country` varchar(128) NOT NULL,
  `payment_country_id` int(11) NOT NULL,
  `payment_zone` varchar(128) NOT NULL,
  `payment_zone_id` int(11) NOT NULL,
  `payment_address_format` text NOT NULL,
  `payment_custom_field` text NOT NULL,
  `payment_method` varchar(128) NOT NULL,
  `payment_code` varchar(128) NOT NULL,
  `shipping_firstname` varchar(32) NOT NULL,
  `shipping_lastname` varchar(32) NOT NULL,
  `shipping_company` varchar(40) NOT NULL,
  `shipping_address_1` varchar(128) NOT NULL,
  `shipping_address_2` varchar(128) NOT NULL,
  `shipping_city` varchar(128) NOT NULL,
  `shipping_postcode` varchar(10) NOT NULL,
  `shipping_country` varchar(128) NOT NULL,
  `shipping_country_id` int(11) NOT NULL,
  `shipping_zone` varchar(128) NOT NULL,
  `shipping_zone_id` int(11) NOT NULL,
  `shipping_address_format` text NOT NULL,
  `shipping_custom_field` text NOT NULL,
  `shipping_method` varchar(128) NOT NULL,
  `shipping_code` varchar(128) NOT NULL,
  `comment` text NOT NULL,
  `total` decimal(15,4) NOT NULL DEFAULT '0.0000',
  `order_status_id` int(11) NOT NULL,
  `affiliate_id` int(11) NOT NULL,
  `commission` decimal(15,4) NOT NULL,
  `marketing_id` int(11) NOT NULL,
  `tracking` varchar(64) NOT NULL,
  `language_id` int(11) NOT NULL,
  `currency_id` int(11) NOT NULL,
  `currency_code` varchar(3) NOT NULL,
  `currency_value` decimal(15,8) NOT NULL DEFAULT '1.00000000',
  `ip` varchar(40) NOT NULL,
  `forwarded_ip` varchar(40) NOT NULL,
  `user_agent` varchar(255) NOT NULL,
  `accept_language` varchar(255) NOT NULL,
  `date_added` datetime NOT NULL,
  `date_modified` datetime NOT NULL,
  `payment_company_id` varchar(32) NOT NULL,
  `payment_tax_id` varchar(32) NOT NULL,
  `review_requested` int(11) NOT NULL DEFAULT '0',
  PRIMARY KEY (`order_id`),
  KEY `store_id` (`store_id`),
  KEY `customer_id` (`customer_id`),
  KEY `customer_group_id` (`customer_group_id`),
  KEY `payment_country_id` (`payment_country_id`),
  KEY `payment_zone_id` (`payment_zone_id`),
  KEY `shipping_country_id` (`shipping_country_id`),
  KEY `shipping_zone_id` (`shipping_zone_id`),
  KEY `order_status_id` (`order_status_id`),
  KEY `affiliate_id` (`affiliate_id`),
  KEY `marketing_id` (`marketing_id`),
  KEY `language_id` (`language_id`),
  KEY `currency_id` (`currency_id`),
  KEY `payment_company_id` (`payment_company_id`),
  KEY `payment_tax_id` (`payment_tax_id`)
) ENGINE=MyISAM AUTO_INCREMENT=39783 DEFAULT CHARSET=utf8 |
+-------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set