https://stackoverflow.com/questions/49539899/mysql-views-polymorphic-associations-and-child-tables

test.sql

# ************************************************************
# Sequel Pro SQL dump
# Version 4541
#
# http://www.sequelpro.com/
# https://github.com/sequelpro/sequelpro
#
# Host: 127.0.0.1 (MySQL 5.7.20)
# Database: test
# Generation Time: 2018-03-29 06:11:45 +0000
# ************************************************************


/*!40101 SET @OLD_CHARACTER_SET_CLIENT=@@CHARACTER_SET_CLIENT */;
/*!40101 SET @OLD_CHARACTER_SET_RESULTS=@@CHARACTER_SET_RESULTS */;
/*!40101 SET @OLD_COLLATION_CONNECTION=@@COLLATION_CONNECTION */;
/*!40101 SET NAMES utf8 */;
/*!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' */;
/*!40111 SET @OLD_SQL_NOTES=@@SQL_NOTES, SQL_NOTES=0 */;


# Dump of table item
# ------------------------------------------------------------

DROP TABLE IF EXISTS `item`;

CREATE TABLE `item` (
  `id` int(11) unsigned NOT NULL AUTO_INCREMENT,
  `transaction_id` int(11) DEFAULT NULL,
  `unit_price` int(11) DEFAULT NULL,
  `quantity` int(11) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

LOCK TABLES `item` WRITE;
/*!40000 ALTER TABLE `item` DISABLE KEYS */;

INSERT INTO `item` (`id`, `transaction_id`, `unit_price`, `quantity`)
VALUES
	(1,1,10,1),
	(2,1,20,1),
	(3,2,30,1),
	(4,2,40,1),
	(5,3,50,1),
	(6,3,60,1),
	(7,4,70,1),
	(8,4,80,1);

/*!40000 ALTER TABLE `item` ENABLE KEYS */;
UNLOCK TABLES;


# Dump of table producer
# ------------------------------------------------------------

DROP TABLE IF EXISTS `producer`;

CREATE TABLE `producer` (
  `id` int(11) unsigned NOT NULL AUTO_INCREMENT,
  `name` varchar(255) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

LOCK TABLES `producer` WRITE;
/*!40000 ALTER TABLE `producer` DISABLE KEYS */;

INSERT INTO `producer` (`id`, `name`)
VALUES
	(1,'foo'),
	(2,'bar');

/*!40000 ALTER TABLE `producer` ENABLE KEYS */;
UNLOCK TABLES;


# Dump of table retailer
# ------------------------------------------------------------

DROP TABLE IF EXISTS `retailer`;

CREATE TABLE `retailer` (
  `id` int(11) unsigned NOT NULL AUTO_INCREMENT,
  `name` varchar(255) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

LOCK TABLES `retailer` WRITE;
/*!40000 ALTER TABLE `retailer` DISABLE KEYS */;

INSERT INTO `retailer` (`id`, `name`)
VALUES
	(1,'baz'),
	(2,'qux');

/*!40000 ALTER TABLE `retailer` ENABLE KEYS */;
UNLOCK TABLES;


# Dump of table transaction
# ------------------------------------------------------------

DROP TABLE IF EXISTS `transaction`;

CREATE TABLE `transaction` (
  `id` int(11) unsigned NOT NULL AUTO_INCREMENT,
  `product` varchar(255) DEFAULT NULL,
  `supplier_id` int(11) DEFAULT NULL,
  `supplier_type` varchar(255) DEFAULT NULL,
  `client_id` int(11) DEFAULT NULL,
  `client_type` varchar(255) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

LOCK TABLES `transaction` WRITE;
/*!40000 ALTER TABLE `transaction` DISABLE KEYS */;

INSERT INTO `transaction` (`id`, `product`, `supplier_id`, `supplier_type`, `client_id`, `client_type`)
VALUES
	(1,'a',1,'App\\Producer',1,'App\\Retailer'),
	(2,'b',2,'App\\Retailer',1,'App\\Retailer'),
	(3,'c',1,'App\\Producer',2,'App\\Producer'),
	(4,'d',2,'App\\Retailer',2,'App\\Producer');

/*!40000 ALTER TABLE `transaction` ENABLE KEYS */;
UNLOCK TABLES;



/*!40111 SET SQL_NOTES=@OLD_SQL_NOTES */;
/*!40101 SET SQL_MODE=@OLD_SQL_MODE */;
/*!40014 SET FOREIGN_KEY_CHECKS=@OLD_FOREIGN_KEY_CHECKS */;
/*!40101 SET CHARACTER_SET_CLIENT=@OLD_CHARACTER_SET_CLIENT */;
/*!40101 SET CHARACTER_SET_RESULTS=@OLD_CHARACTER_SET_RESULTS */;
/*!40101 SET COLLATION_CONNECTION=@OLD_COLLATION_CONNECTION */;