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  • 查询数据库中的重复数据——MySQL数据库

    1、建表语句

    DROP TABLE IF EXISTS `t_people`;
    CREATE TABLE `t_people`  (
      `id` bigint(20) UNSIGNED NOT NULL AUTO_INCREMENT,
      `people_no` varchar(18) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL,
      `people_name` varchar(100) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL,
      PRIMARY KEY (`id`) USING BTREE
    ) ENGINE = InnoDB AUTO_INCREMENT = 11 CHARACTER SET = utf8mb4 COLLATE = utf8mb4_general_ci ROW_FORMAT = Dynamic;
    

    2、插入数据

    INSERT INTO `t_people` VALUES (1, '100', '张三');
    INSERT INTO `t_people` VALUES (2, '100', '张三');
    INSERT INTO `t_people` VALUES (3, '100', '张三');
    INSERT INTO `t_people` VALUES (4, '101', '李四');
    INSERT INTO `t_people` VALUES (5, '101', '李四');
    INSERT INTO `t_people` VALUES (6, '102', '王五');
    INSERT INTO `t_people` VALUES (7, '103', '赵六');
    INSERT INTO `t_people` VALUES (8, '104', '田七');
    INSERT INTO `t_people` VALUES (9, '100', '嘻嘻');
    INSERT INTO `t_people` VALUES (10, '100', '小粉丝');
    

    3、查询 people_no 重复的记录

    SELECT * 
    FROM t_people 
    WHERE people_no IN (
    	SELECT people_no FROM t_people GROUP BY people_no HAVING COUNT(people_no) > 1
    );
    

    4、查询 people_no 重复且不包含 id 最小的记录

    SELECT * 
    FROM t_people 
    WHERE people_no IN (
    	SELECT people_no FROM t_people GROUP BY people_no HAVING COUNT(people_no) > 1
    ) AND id NOT IN (
    	SELECT MIN(id) FROM t_people GROUP BY people_no HAVING COUNT(people_no) > 1
    );
    

    5、查询 people_no 和 people_name 重复的记录

    SELECT * 
    FROM t_people 
    WHERE (people_no, people_name) IN (
    	SELECT people_no, people_name FROM t_people GROUP BY people_no, people_name HAVING COUNT(*) > 1
    );
    

    6、查询 people_no 和 people_name 重复且不包含 id 最小的记录

    SELECT * 
    FROM t_people 
    WHERE (people_no, people_name) IN (
    	SELECT people_no, people_name FROM t_people GROUP BY people_no, people_name HAVING COUNT(*) > 1 
    ) AND id NOT IN (
    	SELECT MIN(id) FROM t_people GROUP BY people_no, people_name HAVING COUNT(*) > 1
    );
    

    本文参考:https://www.cnblogs.com/LDDXFS/p/9867928.html

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  • 原文地址:https://www.cnblogs.com/qubo520/p/13529702.html
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