mysql查询重复用户最新的一条数据

Posted 2021-03-20 官萧何

mysql使用distinct（关键）+ order by + group 查询成绩表中每个学生时间最近的成绩数据

sql初始化

-- --------------------------------------------------------
-- 主机:                           127.0.0.1
-- 服务器版本:                        8.0.15 - MySQL Community Server - GPL
-- 服务器操作系统:                      Win64
-- HeidiSQL 版本:                  9.5.0.5196
-- --------------------------------------------------------

/*!40101 SET @OLD_CHARACTER_SET_CLIENT=@@CHARACTER_SET_CLIENT */;
/*!40101 SET NAMES utf8 */;
/*!50503 SET NAMES utf8mb4 */;
/*!40014 SET @OLD_FOREIGN_KEY_CHECKS=@@FOREIGN_KEY_CHECKS, FOREIGN_KEY_CHECKS=0 */;
/*!40101 SET @OLD_SQL_MODE=@@SQL_MODE, SQL_MODE=‘NO_AUTO_VALUE_ON_ZERO‘ */;

-- 导出  表 test.score 结构
CREATE TABLE IF NOT EXISTS `score` (
  `score_id` bigint(20) NOT NULL AUTO_INCREMENT,
  `student_name` varchar(32) DEFAULT NULL,
  `course` varchar(30) DEFAULT NULL,
  `score` int(11) DEFAULT NULL,
  `create_time` datetime DEFAULT CURRENT_TIMESTAMP,
  PRIMARY KEY (`score_id`)
) ENGINE=InnoDB AUTO_INCREMENT=10 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci;

-- 正在导出表  test.score 的数据：~8 rows (大约)
/*!40000 ALTER TABLE `score` DISABLE KEYS */;
INSERT INTO `score` (`score_id`, `student_name`, `course`, `score`, `create_time`) VALUES
    (1, ‘张三‘, ‘语文‘, 66, ‘2019-07-24 10:35:05‘),
    (2, ‘张三‘, ‘数学‘, 88, ‘2019-12-24 10:35:05‘),
    (3, ‘张三‘, ‘英语‘, 92, ‘2019-02-24 10:35:05‘),
    (4, ‘李四‘, ‘语文‘, 95, ‘2019-06-24 10:35:05‘),
    (5, ‘李四‘, ‘数学‘, 55, ‘2019-08-24 10:35:05‘),
    (6, ‘李四‘, ‘英语‘, 22, ‘2019-03-24 10:35:05‘),
    (7, ‘王五‘, ‘语文‘, 99, ‘2019-06-23 10:35:05‘),
    (8, ‘王五‘, ‘数学‘, 88, ‘2019-08-24 10:35:05‘),
    (9, ‘王五‘, ‘英语‘, 77, ‘2019-05-24 10:35:05‘);
/*!40000 ALTER TABLE `score` ENABLE KEYS */;

/*!40101 SET SQL_MODE=IFNULL(@OLD_SQL_MODE, ‘‘) */;
/*!40014 SET FOREIGN_KEY_CHECKS=IF(@OLD_FOREIGN_KEY_CHECKS IS NULL, 1, @OLD_FOREIGN_KEY_CHECKS) */;
/*!40101 SET CHARACTER_SET_CLIENT=@OLD_CHARACTER_SET_CLIENT */;

执行sql

SELECT
    *
FROM
    (
        SELECT DISTINCT
            *
        FROM
            score
        ORDER BY
            create_time DESC
    ) s
GROUP BY
    s.student_name;

结果展示

2 张三 数学 88 2019-12-24 10:35:05
5 李四 数学 55 2019-08-24 10:35:05
8 王五 数学 88 2019-08-24 10:35:05