MySQL 8.0

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CREATE TABLE `clients_basses` (
   `id` INT(10) NOT NULL AUTO_INCREMENT,
   `name` VARCHAR(50) NULL DEFAULT NULL COLLATE 'utf8mb4_0900_ai_ci',
    PRIMARY KEY (`id`) USING BTREE
)COLLATE='utf8_general_ci' ENGINE=InnoDB AUTO_INCREMENT=2;
INSERT INTO `clients_basses` VALUES (1, 'База клиентов 1');
SELECT * FROM clients_basses;
CREATE TABLE `clients` (
   `id` INT(10) NOT NULL AUTO_INCREMENT,
   `base_id` INT(10) NOT NULL,
   `ctreated_at` TIMESTAMP NULL DEFAULT NULL,
   `updated_at` TIMESTAMP NULL DEFAULT NULL,
   PRIMARY KEY (`id`) USING BTREE,
   INDEX `FK_clients_clients_basses` (`base_id`) USING BTREE,
   CONSTRAINT `FK_clients_clients_basses` FOREIGN KEY (`base_id`) REFERENCES 
   `clients_basses` (`id`) ON UPDATE CASCADE ON DELETE CASCADE
) COLLATE='utf8mb4_0900_ai_ci' ENGINE=InnoDB AUTO_INCREMENT=2;
INSERT INTO `clients` VALUES (1, 1, '2021-03-18 20:45:18', '2021-03-18 20:45:20');
SELECT * FROM clients;
CREATE TABLE `client_fields` (
   `id` INT(10) NOT NULL AUTO_INCREMENT,
   `base_id` INT(10) NOT NULL,
   `client_id` INT(10) NOT NULL,
   `label` VARCHAR(255) NULL DEFAULT NULL COLLATE 'utf8mb4_0900_ai_ci',
   `key` VARCHAR(255) NULL DEFAULT NULL COLLATE 'utf8mb4_0900_ai_ci',
   PRIMARY KEY (`id`) USING BTREE,
   INDEX `FK_client_fields_clients_basses` (`base_id`) USING BTREE,
   INDEX `FK_client_fields_clients` (`client_id`) USING BTREE,
   CONSTRAINT `FK_client_fields_clients` FOREIGN KEY (`client_id`) REFERENCES 
   `clients` (`id`) ON UPDATE NO ACTION ON DELETE NO ACTION,
   CONSTRAINT `FK_client_fields_clients_basses` FOREIGN KEY (`base_id`) 
   REFERENCES `clients_basses` (`id`) ON UPDATE CASCADE ON DELETE CASCADE) COLLATE='utf8mb4_0900_ai_ci' ENGINE=InnoDB AUTO_INCREMENT=4;
INSERT INTO `client_fields` VALUES (1, 1, 1, 'Имя', 'name');
INSERT INTO `client_fields` VALUES (2, 1, 1, 'Телефон', 'phone');
INSERT INTO `client_fields` VALUES (3, 1, 1, 'Возраст', 'age');
SELECT * FROM client_fields;
CREATE TABLE `client_values` (
    `id` INT(10) NOT NULL AUTO_INCREMENT,
    `field_id` INT(10) NOT NULL,
    `base_id` INT(10) NULL DEFAULT NULL,
    `value` VARCHAR(255) NULL DEFAULT NULL COLLATE 'utf8mb4_0900_ai_ci',
    PRIMARY KEY (`id`) USING BTREE,
    INDEX `FK__client_fields` (`field_id`) USING BTREE,
    INDEX `FK_client_values_clients_basses` (`base_id`) USING BTREE,
    CONSTRAINT `FK_client_values_clients_basses` FOREIGN KEY (`base_id`) REFERENCES `clients_basses` (`id`) ON UPDATE NO ACTION ON DELETE NO ACTION,
    CONSTRAINT `FK__client_fields` FOREIGN KEY (`field_id`) REFERENCES `client_fields` (`id`) ON UPDATE NO ACTION ON DELETE NO ACTION
) COLLATE='utf8mb4_0900_ai_ci' ENGINE=InnoDB AUTO_INCREMENT=5;
INSERT INTO `client_values` VALUES (1, 1, 1, 'Роман');
INSERT INTO `client_values` VALUES (2, 2, 1, '991');
INSERT INTO `client_values` VALUES (3, 2, 1, '103');
INSERT INTO `client_values` VALUES (4, 3, 1, '26');
SELECT * FROM client_values;


id
name


1
База клиентов 1




id
base_id
ctreated_at
updated_at


1
1
2021-03-18 20:45:18
2021-03-18 20:45:20




id
base_id
client_id
label
key


1
1
1
Имя
name

2
1
1
Телефон
phone

3
1
1
Возраст
age




id
field_id
base_id
value


1
1
1
Роман

2
2
1
991

3
2
1
103

4
3
1
26


-- Для справки - объединяющий запрос. 
-- Используется как основа для вьюхи.
SELECT *
FROM clients_basses cb
JOIN clients c ON c.base_id = cb.id
JOIN client_fields cf ON cf.client_id = c.id
                     AND cf.base_id = cb.id -- избыточно
JOIN client_values cv ON cv.field_id = cf.id
                     AND cv.base_id = cb.id -- избыточно


id
name
id
base_id
ctreated_at
updated_at
id
base_id
client_id
label
key
id
field_id
base_id
value


1
База клиентов 1
1
1
2021-03-18 20:45:18
2021-03-18 20:45:20
1
1
1
Имя
name
1
1
1
Роман

1
База клиентов 1
1
1
2021-03-18 20:45:18
2021-03-18 20:45:20
2
1
1
Телефон
phone
2
2
1
991

1
База клиентов 1
1
1
2021-03-18 20:45:18
2021-03-18 20:45:20
2
1
1
Телефон
phone
3
2
1
103

1
База клиентов 1
1
1
2021-03-18 20:45:18
2021-03-18 20:45:20
3
1
1
Возраст
age
4
3
1
26


-- Вьюха. Базха для построения сводной таблицы
CREATE VIEW complete_data AS
SELECT c.id, cf.label, GROUP_CONCAT(cv.value) value
FROM clients_basses cb
JOIN clients c ON c.base_id = cb.id
JOIN client_fields cf ON cf.client_id = c.id
JOIN client_values cv ON cv.field_id = cf.id
GROUP BY c.id, cf.label;

SELECT * FROM complete_data;


id
label
value


1
Возраст
26

1
Имя
Роман

1
Телефон
991,103


-- Хранимая процедура формирования сводной таблицы.
CREATE PROCEDURE pivot (tablename VARCHAR(64),
                        groupname VARCHAR(64),
                        pivotname VARCHAR(64),
                        valuename VARCHAR(64))
BEGIN
SELECT CONCAT('CREATE VIEW to_columnslist AS\n',
              'SELECT DISTINCT CONCAT(\'`\', `', pivotname,'`, \'` VARCHAR(255) path \\\'$."\', ', pivotname,', \'"\\\'\') line\n',
              'FROM ', tablename)
INTO @sql;
PREPARE stmt FROM @sql;
EXECUTE stmt;
DROP PREPARE stmt;
SELECT CONCAT(
'SELECT to_json.`', groupname,'`, parsed.*', '\n',
'FROM (SELECT `', groupname,'`, JSON_OBJECTAGG(`', pivotname,'`, `', valuename,'`) json_data', '\n',
'      FROM `', tablename,'`', '\n',
'      GROUP BY `', groupname,'`) to_json', '\n',
'CROSS JOIN JSON_TABLE( json_data,', '\n',
'                       "$" COLUMNS ( ', 
GROUP_CONCAT(line SEPARATOR ',\n                                     '),
' ) ) parsed'
) sql_text
INTO @sql
FROM to_columnslist;
PREPARE stmt FROM @sql;
EXECUTE stmt;
DROP PREPARE stmt;
DROP VIEW to_columnslist;
END
-- получаем результат
CALL pivot ('complete_data', 'id', 'label', 'value');


id
Возраст
Имя
Телефон


1
26
Роман
991,103
id	name	id	base_id	ctreated_at	updated_at	id	base_id	client_id	label	key	id	field_id	base_id	value
1	База клиентов 1	1	1	2021-03-18 20:45:18	2021-03-18 20:45:20	1	1	1	Имя	name	1	1	1	Роман
1	База клиентов 1	1	1	2021-03-18 20:45:18	2021-03-18 20:45:20	2	1	1	Телефон	phone	2	2	1	991
1	База клиентов 1	1	1	2021-03-18 20:45:18	2021-03-18 20:45:20	2	1	1	Телефон	phone	3	2	1	103
1	База клиентов 1	1	1	2021-03-18 20:45:18	2021-03-18 20:45:20	3	1	1	Возраст	age	4	3	1	26