mysql 5.7.2 语句 GROUP_CONCAT正确排序

SET NAMES utf8mb4;
SET FOREIGN_KEY_CHECKS = 0;


-- ----------------------------
-- Table structure for demo
-- ----------------------------
DROP TABLE IF EXISTS `demo`;
CREATE TABLE `demo`  (
  `id` bigint(20) NOT NULL AUTO_INCREMENT,
  `name` char(20) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL,
  `score` bigint(20) DEFAULT NULL,
  PRIMARY KEY (`id`) USING BTREE
) ENGINE = InnoDB AUTO_INCREMENT = 45 CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = Dynamic;
-- ----------------------------
-- Records of demo
-- ----------------------------
INSERT INTO `demo` VALUES (1, '张三14', 60);
INSERT INTO `demo` VALUES (2, '张三14', 54);
INSERT INTO `demo` VALUES (15, '张三14', 61);
INSERT INTO `demo` VALUES (16, '张三15', 12);
INSERT INTO `demo` VALUES (17, '张三16', 54);
INSERT INTO `demo` VALUES (18, '张三17', 33);
INSERT INTO `demo` VALUES (41, '张三', 54);
INSERT INTO `demo` VALUES (42, '张三', 89);
INSERT INTO `demo` VALUES (43, '张三', 48);
INSERT INTO `demo` VALUES (44, '张三', 98);


SET FOREIGN_KEY_CHECKS = 1;

mysql 中 group_concat()，手册上说明:该函数返回带有来自一个组的连接的非NULL值的字符串结果。

我们想根据name分组，然后根据score倒序排序，下面展示两种写法；

注意：sql一：错误排序语句：SELECT name,GROUP_CONCAT(score ORDER BY score DESC) AS myScore FROM demo GROUP BY name

这种是错误的下面的不是根据GROUP_CONCAT拼接的数据是不会排序的

sql二：正确排序语句：SELECT name,GROUP_CONCAT(score ORDER BY score DESC) AS myScore FROM demo GROUP BY name order by myScore desc;

必须根据排序后的字段二次排序，第一次只能是排序GROUP_CONCAT里边的如果没有分组的是无法排序的，只能分完组后再根据myScore排序

在mysql5.72上已测试