MySQL中将多行查询结果合并为一行展示SQL语句书写

2022-09-07 13:36:18

写在前面

　　最近开发过程中，遇到一个需求是要将所查询的多条结果汇总成一条结果展示，由于之前没有接触过这方面的业务，所以经过一番折腾之后，解决了需求，这里特此记录一下，以供后续参考！

1、问题复现

这里以一个例子进行说明：

需求：一个员工每月是否完成了打卡，要求统计员工当月完成和未完成日期，展示结果如下：

MySQL中将多行查询结果合并为一行展示SQL语句书写

测试的数据库表字段如下：

CREATE TABLE `time_summary` (
  `id` int NOT NULL AUTO_INCREMENT,
  `emp_id` varchar(20) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci DEFAULT NULL COMMENT ‘员工号‘,
  `emp_name` varchar(30) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci DEFAULT NULL COMMENT ‘员工姓名‘,
  `time_date` date DEFAULT NULL COMMENT ‘填报日期‘,
  `finish_flag` varchar(10) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci DEFAULT NULL COMMENT ‘完成标志：0：未完成，1：已完成‘,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci;

测试数据如下：

INSERT INTO `time_summary`(`id`, `emp_id`, `emp_name`, `time_date`, `finish_flag`) VALUES (1, ‘100‘, ‘张三‘, ‘2020-06-24‘, ‘0‘);
INSERT INTO `time_summary`(`id`, `emp_id`, `emp_name`, `time_date`, `finish_flag`) VALUES (2, ‘100‘, ‘张三‘, ‘2020-06-23‘, ‘0‘);
INSERT INTO `time_summary`(`id`, `emp_id`, `emp_name`, `time_date`, `finish_flag`) VALUES (3, ‘100‘, ‘张三‘, ‘2020-06-22‘, ‘0‘);
INSERT INTO `time_summary`(`id`, `emp_id`, `emp_name`, `time_date`, `finish_flag`) VALUES (4, ‘100‘, ‘张三‘, ‘2020-06-19‘, ‘0‘);
INSERT INTO `time_summary`(`id`, `emp_id`, `emp_name`, `time_date`, `finish_flag`) VALUES (5, ‘100‘, ‘张三‘, ‘2020-06-18‘, ‘0‘);
INSERT INTO `time_summary`(`id`, `emp_id`, `emp_name`, `time_date`, `finish_flag`) VALUES (6, ‘100‘, ‘张三‘, ‘2020-06-17‘, ‘0‘);
INSERT INTO `time_summary`(`id`, `emp_id`, `emp_name`, `time_date`, `finish_flag`) VALUES (7, ‘100‘, ‘张三‘, ‘2020-06-16‘, ‘0‘);
INSERT INTO `time_summary`(`id`, `emp_id`, `emp_name`, `time_date`, `finish_flag`) VALUES (8, ‘100‘, ‘张三‘, ‘2020-06-15‘, ‘0‘);
INSERT INTO `time_summary`(`id`, `emp_id`, `emp_name`, `time_date`, `finish_flag`) VALUES (9, ‘100‘, ‘张三‘, ‘2020-06-12‘, ‘1‘);
INSERT INTO `time_summary`(`id`, `emp_id`, `emp_name`, `time_date`, `finish_flag`) VALUES (10, ‘100‘, ‘张三‘, ‘2020-06-11‘, ‘1‘);
INSERT INTO `time_summary`(`id`, `emp_id`, `emp_name`, `time_date`, `finish_flag`) VALUES (11, ‘100‘, ‘张三‘, ‘2020-06-10‘, ‘1‘);
INSERT INTO `time_summary`(`id`, `emp_id`, `emp_name`, `time_date`, `finish_flag`) VALUES (12, ‘100‘, ‘张三‘, ‘2020-06-09‘, ‘1‘);
INSERT INTO `time_summary`(`id`, `emp_id`, `emp_name`, `time_date`, `finish_flag`) VALUES (13, ‘100‘, ‘张三‘, ‘2020-06-08‘, ‘1‘);
INSERT INTO `time_summary`(`id`, `emp_id`, `emp_name`, `time_date`, `finish_flag`) VALUES (14, ‘100‘, ‘张三‘, ‘2020-06-05‘, ‘0‘);
INSERT INTO `time_summary`(`id`, `emp_id`, `emp_name`, `time_date`, `finish_flag`) VALUES (15, ‘100‘, ‘张三‘, ‘2020-06-04‘, ‘0‘);
INSERT INTO `time_summary`(`id`, `emp_id`, `emp_name`, `time_date`, `finish_flag`) VALUES (16, ‘100‘, ‘张三‘, ‘2020-06-03‘, ‘0‘);
INSERT INTO `time_summary`(`id`, `emp_id`, `emp_name`, `time_date`, `finish_flag`) VALUES (17, ‘100‘, ‘张三‘, ‘2020-06-02‘, ‘0‘);
INSERT INTO `time_summary`(`id`, `emp_id`, `emp_name`, `time_date`, `finish_flag`) VALUES (18, ‘100‘, ‘张三‘, ‘2020-06-01‘, ‘0‘);
INSERT INTO `time_summary`(`id`, `emp_id`, `emp_name`, `time_date`, `finish_flag`) VALUES (19, ‘101‘, ‘李四‘, ‘2020-06-24‘, ‘0‘);
INSERT INTO `time_summary`(`id`, `emp_id`, `emp_name`, `time_date`, `finish_flag`) VALUES (20, ‘101‘, ‘李四‘, ‘2020-06-23‘, ‘0‘);
INSERT INTO `time_summary`(`id`, `emp_id`, `emp_name`, `time_date`, `finish_flag`) VALUES (21, ‘101‘, ‘李四‘, ‘2020-06-22‘, ‘0‘);
INSERT INTO `time_summary`(`id`, `emp_id`, `emp_name`, `time_date`, `finish_flag`) VALUES (22, ‘101‘, ‘李四‘, ‘2020-06-19‘, ‘0‘);
INSERT INTO `time_summary`(`id`, `emp_id`, `emp_name`, `time_date`, `finish_flag`) VALUES (23, ‘101‘, ‘李四‘, ‘2020-06-18‘, ‘0‘);
INSERT INTO `time_summary`(`id`, `emp_id`, `emp_name`, `time_date`, `finish_flag`) VALUES (24, ‘101‘, ‘李四‘, ‘2020-06-17‘, ‘0‘);
INSERT INTO `time_summary`(`id`, `emp_id`, `emp_name`, `time_date`, `finish_flag`) VALUES (25, ‘101‘, ‘李四‘, ‘2020-06-16‘, ‘0‘);
INSERT INTO `time_summary`(`id`, `emp_id`, `emp_name`, `time_date`, `finish_flag`) VALUES (26, ‘101‘, ‘李四‘, ‘2020-06-15‘, ‘0‘);
INSERT INTO `time_summary`(`id`, `emp_id`, `emp_name`, `time_date`, `finish_flag`) VALUES (27, ‘101‘, ‘李四‘, ‘2020-06-12‘, ‘0‘);
INSERT INTO `time_summary`(`id`, `emp_id`, `emp_name`, `time_date`, `finish_flag`) VALUES (28, ‘101‘, ‘李四‘, ‘2020-06-11‘, ‘0‘);
INSERT INTO `time_summary`(`id`, `emp_id`, `emp_name`, `time_date`, `finish_flag`) VALUES (29, ‘101‘, ‘李四‘, ‘2020-06-10‘, ‘0‘);
INSERT INTO `time_summary`(`id`, `emp_id`, `emp_name`, `time_date`, `finish_flag`) VALUES (30, ‘101‘, ‘李四‘, ‘2020-06-09‘, ‘0‘);
INSERT INTO `time_summary`(`id`, `emp_id`, `emp_name`, `time_date`, `finish_flag`) VALUES (31, ‘101‘, ‘李四‘, ‘2020-06-08‘, ‘1‘);
INSERT INTO `time_summary`(`id`, `emp_id`, `emp_name`, `time_date`, `finish_flag`) VALUES (32, ‘101‘, ‘李四‘, ‘2020-06-05‘, ‘1‘);
INSERT INTO `time_summary`(`id`, `emp_id`, `emp_name`, `time_date`, `finish_flag`) VALUES (33, ‘101‘, ‘李四‘, ‘2020-06-04‘, ‘0‘);
INSERT INTO `time_summary`(`id`, `emp_id`, `emp_name`, `time_date`, `finish_flag`) VALUES (34, ‘101‘, ‘李四‘, ‘2020-06-03‘, ‘0‘);
INSERT INTO `time_summary`(`id`, `emp_id`, `emp_name`, `time_date`, `finish_flag`) VALUES (35, ‘101‘, ‘李四‘, ‘2020-06-02‘, ‘0‘);
INSERT INTO `time_summary`(`id`, `emp_id`, `emp_name`, `time_date`, `finish_flag`) VALUES (36, ‘101‘, ‘李四‘, ‘2020-06-01‘, ‘0‘);
INSERT INTO `time_summary`(`id`, `emp_id`, `emp_name`, `time_date`, `finish_flag`) VALUES (37, ‘102‘, ‘王五‘, ‘2020-06-24‘, ‘1‘);
INSERT INTO `time_summary`(`id`, `emp_id`, `emp_name`, `time_date`, `finish_flag`) VALUES (38, ‘102‘, ‘王五‘, ‘2020-06-23‘, ‘1‘);
INSERT INTO `time_summary`(`id`, `emp_id`, `emp_name`, `time_date`, `finish_flag`) VALUES (39, ‘102‘, ‘王五‘, ‘2020-06-22‘, ‘1‘);
INSERT INTO `time_summary`(`id`, `emp_id`, `emp_name`, `time_date`, `finish_flag`) VALUES (40, ‘102‘, ‘王五‘, ‘2020-06-19‘, ‘1‘);
INSERT INTO `time_summary`(`id`, `emp_id`, `emp_name`, `time_date`, `finish_flag`) VALUES (41, ‘102‘, ‘王五‘, ‘2020-06-18‘, ‘1‘);
INSERT INTO `time_summary`(`id`, `emp_id`, `emp_name`, `time_date`, `finish_flag`) VALUES (42, ‘102‘, ‘王五‘, ‘2020-06-17‘, ‘0‘);
INSERT INTO `time_summary`(`id`, `emp_id`, `emp_name`, `time_date`, `finish_flag`) VALUES (43, ‘102‘, ‘王五‘, ‘2020-06-16‘, ‘0‘);
INSERT INTO `time_summary`(`id`, `emp_id`, `emp_name`, `time_date`, `finish_flag`) VALUES (44, ‘102‘, ‘王五‘, ‘2020-06-15‘, ‘0‘);
INSERT INTO `time_summary`(`id`, `emp_id`, `emp_name`, `time_date`, `finish_flag`) VALUES (45, ‘102‘, ‘王五‘, ‘2020-06-12‘, ‘0‘);
INSERT INTO `time_summary`(`id`, `emp_id`, `emp_name`, `time_date`, `finish_flag`) VALUES (46, ‘102‘, ‘王五‘, ‘2020-06-11‘, ‘0‘);
INSERT INTO `time_summary`(`id`, `emp_id`, `emp_name`, `time_date`, `finish_flag`) VALUES (47, ‘102‘, ‘王五‘, ‘2020-06-10‘, ‘1‘);
INSERT INTO `time_summary`(`id`, `emp_id`, `emp_name`, `time_date`, `finish_flag`) VALUES (48, ‘102‘, ‘王五‘, ‘2020-06-09‘, ‘1‘);
INSERT INTO `time_summary`(`id`, `emp_id`, `emp_name`, `time_date`, `finish_flag`) VALUES (49, ‘102‘, ‘王五‘, ‘2020-06-08‘, ‘1‘);
INSERT INTO `time_summary`(`id`, `emp_id`, `emp_name`, `time_date`, `finish_flag`) VALUES (50, ‘102‘, ‘王五‘, ‘2020-06-05‘, ‘1‘);
INSERT INTO `time_summary`(`id`, `emp_id`, `emp_name`, `time_date`, `finish_flag`) VALUES (51, ‘102‘, ‘王五‘, ‘2020-06-04‘, ‘0‘);
INSERT INTO `time_summary`(`id`, `emp_id`, `emp_name`, `time_date`, `finish_flag`) VALUES (52, ‘102‘, ‘王五‘, ‘2020-06-03‘, ‘0‘);
INSERT INTO `time_summary`(`id`, `emp_id`, `emp_name`, `time_date`, `finish_flag`) VALUES (53, ‘102‘, ‘王五‘, ‘2020-06-02‘, ‘0‘);
INSERT INTO `time_summary`(`id`, `emp_id`, `emp_name`, `time_date`, `finish_flag`) VALUES (54, ‘102‘, ‘王五‘, ‘2020-06-01‘, ‘0‘);

这种情况下，我们一般可以将所有的情况查询出来(这里以6月份数据为例)，查询SQL如下：

SELECT t.emp_id,t.emp_name,t.time_date,t.finish_flag from time_summary t 
where t.time_date >= ‘2020-06-01‘ and time_date <= ‘2020-06-30‘

这样查询的结果如下：

MySQL中将多行查询结果合并为一行展示SQL语句书写

 这种显然不满足要求，针对这种情况，要怎么做呢？

 2、问题解决

这时候需要使用 GROUP_CONCAT() 函数解决此问题。

说明：

1.GROUP_CONCAT() 中的值为你要合并的数据的字段名;

　SEPARATOR 函数是用来分隔这些要合并的数据的；

　‘ ‘中是你要用哪个符号来分隔；

2.必须要用GROUP BY 语句来进行分组管理，不然所有的数据都会被合并成一条记录

则此处对应的SQL语句如下，仅供参考！

SELECT
    su.emp_id,
    su.emp_name,
    a.notFinished,
    b.finished 
FROM
    (
    SELECT
        t.emp_id,
        t.emp_name 
    FROM
        time_summary t 
    WHERE
        t.time_date >= ‘2020-06-01‘ 
        AND t.time_date <= ‘2020-06-30‘ 
    GROUP BY
        t.emp_id,
        t.emp_name 
    ) su
    LEFT JOIN (
    SELECT
        t.emp_id,
        t.emp_name,
        GROUP_CONCAT( SUBSTRING( t.time_date, 9, 2 ) SEPARATOR ‘,‘ ) AS notFinished 
    FROM
        time_summary t 
    WHERE
        t.time_date >= ‘2020-06-01‘ 
        AND t.time_date <= ‘2020-06-30‘ 
        AND t.finish_flag = ‘0‘ 
    GROUP BY
        t.emp_id,
        t.emp_name 
    ) a ON su.emp_id = a.emp_id
    LEFT JOIN (
    SELECT
        t.emp_id,
        t.emp_name,
        GROUP_CONCAT( SUBSTRING( t.time_date, 9, 2 ) SEPARATOR ‘,‘ ) AS finished 
    FROM
        time_summary t 
    WHERE
        t.time_date >= ‘2020-06-01‘ 
        AND t.time_date <= ‘2020-06-30‘ 
        AND t.finish_flag = ‘1‘ 
    GROUP BY
        t.emp_id,
        t.emp_name 
    ) b ON su.emp_id = b.emp_id

MySQL中将多行查询结果合并为一行展示SQL语句书写

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