我如何在mysql中获得预览产品和下一个产品？

Question

我如何在mysql中获得预览产品和下一个产品？ 例如：当前产品是id 7，我想在表p中获得5和8，如何编写sql？

SET FOREIGN_KEY_CHECKS=0;

-- ----------------------------
-- Table structure for `p`
-- ----------------------------
DROP TABLE IF EXISTS `p`;
CREATE TABLE `p` (
  `id` int(10) NOT NULL auto_increment,
  `products_name` varchar(200) default NULL,
  PRIMARY KEY  (`id`)
) ENGINE=MyISAM AUTO_INCREMENT=12 DEFAULT CHARSET=utf8;

-- ----------------------------
-- Records of p
-- ----------------------------
INSERT INTO `p` VALUES ('1', 'a');
INSERT INTO `p` VALUES ('2', 'b');
INSERT INTO `p` VALUES ('4', 'd');
INSERT INTO `p` VALUES ('5', 'ed');
INSERT INTO `p` VALUES ('11', 'f');
INSERT INTO `p` VALUES ('7', 'gs');
INSERT INTO `p` VALUES ('8', 'd');
INSERT INTO `p` VALUES ('9', 'f');

Answer 1

SELECT P1.id,
       P1.Products_Name
FROM P P1
INNER JOIN
(SELECT max(id)as ID FROM P WHERE id < 7
 UNION ALL
 SELECT min(id)as ID FROM P WHERE id > 7
)T ON T.ID = P1.ID
ORDER BY P1.ID ASC

sqlFiddle example here

Answer 2

你可以使用HANDLER来实现这一点，但这不是标准的。顺便说一句，你想要的只有标准SQL。

mysql> HANDLER p OPEN;
Query OK, 0 rows affected (0.00 sec)

mysql> HANDLER p READ `PRIMARY` = (7);
+----+---------------+
| id | products_name |
+----+---------------+
|  7 | gs            |
+----+---------------+
1 row in set (0.00 sec)

mysql> HANDLER p READ `PRIMARY` NEXT;
+----+---------------+
| id | products_name |
+----+---------------+
|  8 | d             |
+----+---------------+
1 row in set (0.00 sec)

mysql>  HANDLER p READ `PRIMARY` PREV LIMIT 1,1;
+----+---------------+
| id | products_name |
+----+---------------+
|  5 | ed            |
+----+---------------+