mysql实现先分组后排序取N个

SET FOREIGN_KEY_CHECKS=0;

-- ----------------------------
-- Table structure for `test`
-- ----------------------------
DROP TABLE IF EXISTS `test`;
CREATE TABLE `test` (
  `company` varchar(255) DEFAULT NULL,
  `product` varchar(255) DEFAULT NULL,
  `price` int(11) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

-- ----------------------------
-- Records of test
-- ----------------------------
INSERT INTO `test` VALUES ('a', 'a1', '11');
INSERT INTO `test` VALUES ('a', 'a2', '22');
INSERT INTO `test` VALUES ('a', 'a3', '33');
INSERT INTO `test` VALUES ('b', 'b1', '99');
INSERT INTO `test` VALUES ('b', 'b2', '88');
INSERT INTO `test` VALUES ('b', 'b3', '77');
INSERT INTO `test` VALUES ('b', 'b4', '66');
INSERT INTO `test` VALUES ('c', 'c1', '44');
INSERT INTO `test` VALUES ('c', 'c2', '55');
INSERT INTO `test` VALUES ('c', 'c3', '66');
INSERT INTO `test` VALUES ('c', 'c4', '77');

 

--方式一

select * from test t1 where 3 > (select count(*) + 1  from test where company = t1.company and price > t1.price ) order by company , price desc

 

-- 方式二

select * from (
select *  ,(select count(*) + 1 from test where company = t1.company and price > t1.price) group_id
from test t1) t
where group_id < 3
order by t.company , t.price desc

转载于:https://my.oschina.net/vonmomo/blog/862098