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  • MySQL++:MySQL 多行数据合并 GROUP_CONCAT

    表结构及数据:

    DROP TABLE IF EXISTS `course`;
    CREATE TABLE `course` (
    `name` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL,
    `course_name` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL
    ) ENGINE = InnoDB CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = Dynamic;

    -- ----------------------------
    -- Records of course
    -- ----------------------------
    INSERT INTO `course` VALUES ('李明', '阅读赏析');
    INSERT INTO `course` VALUES ('李明', '摄影');
    INSERT INTO `course` VALUES ('李明', '太极剑');
    INSERT INTO `course` VALUES ('司马光', '马克思主义基本原理');
    INSERT INTO `course` VALUES ('司马光', '摄影');
    INSERT INTO `course` VALUES ('叶问', '阅读赏析');
    INSERT INTO `course` VALUES ('叶问', '法语');

    SET FOREIGN_KEY_CHECKS = 1;

    选修课程表

    select t.name as '姓名',t.course_name as '课程' from course t  ;

    需求: 将每个人的课程合并为一行数据

    select t.name as '姓名',GROUP_CONCAT(t.course_name )  as '课程' from course t  group by t.name ;

    修改分隔符及排序

    select t.name as '姓名',GROUP_CONCAT(t.course_name  order by t.course_name SEPARATOR '#')  as '课程' from course t  group by t.name 

    注意:使用 GROUP_CONCAT()函数必须对源数据进行分组,否则所有数据会被合并成一行

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  • 原文地址:https://www.cnblogs.com/codingmode/p/13925651.html
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