datetime字段默认值问题

DROP TABLE IF EXISTS `promo`;

CREATE TABLE `promo`  (

  `id` int NOT NULL,

  `promo_naem` varchar(255) CHARACTER SET utf8 COLLATE utf8_unicode_ci NOT NULL DEFAULT '',

  `start_date` datetime NOT NULL DEFAULT '0000-00-00 00:00:00',

  `item_id` int NOT NULL DEFAULT 0,

  `promo_item_price` double NOT NULL DEFAULT 0,

  PRIMARY KEY (`id`) USING BTREE

) ENGINE = InnoDB CHARACTER SET = utf8 COLLATE = utf8_unicode_ci ROW_FORMAT = Dynamic;

SET FOREIGN_KEY_CHECKS = 1;