DATA TYPE DOUBLE

[Alain Terranova]

Hello,

I created this table:

CREATE TABLE `tbl_coupons_test` (
  `ID_COUPON` int(11) NOT NULL AUTO_INCREMENT,
  `Price_TVAC_01` double DEFAULT NULL,
  `purchase_price` double DEFAULT NULL,
  PRIMARY KEY (`ID_COUPON`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;

Here's his contained:

+-----------+---------------+----------------+
| ID_COUPON | price_tvac_01 | purchase_price |
+-----------+---------------+----------------+
|    600605 |        854.05 |         854.05 |
+-----------+---------------+----------------+

I would like to understand why this query return 1 record:

SELECT 
ID_COUPON, price_tvac_01, purchase_price
FROM
tbl_coupons_test
WHERE `ID_COUPON` = 600605 
AND `price_tvac_01` = 8.54049999999999950e+002;
+-----------+---------------+----------------+
| ID_COUPON | price_tvac_01 | purchase_price |
+-----------+---------------+----------------+
|    600605 |        854.05 |         854.05 |
+-----------+---------------+----------------+
1 row in set

And this one, return nothing:

SELECT 
ID_COUPON, price_tvac_01, purchase_price
FROM
tbl_coupons_test
WHERE `ID_COUPON` = 600605 
AND `purchase_price` = 8.54049999999999950e+002;

Empty set

Does somebody can give me an explaination?

Thanks in advance.

Alain