CRUD NO MAGENTO 2 A PARTIR DO ZEND2

1) Buscando a tabela no banco

 $objectManager = \Magento\Framework\App\ObjectManager::getInstance();
 $resource = $objectManager->get('Magento\Framework\App\ResourceConnection');
 $connection = $resource->getConnection();
 $tableName = $resource->getTableName('clientela');
 

onde clientela é o nome da tabela

2) CRUD

 // INSERT DATA
 $name = 'Mukesh Chapagain';
 $age = 99;
 $email = 'mukesh@example.com';
 $sql = "INSERT INTO " . $tableName . " (id, name, age, email) VALUES ('', '$name', $age, '$email')";
 $connection->query($sql);
 $sql = "INSERT INTO " . $tableName . " (id, name, age, email) VALUES ('', 'Hello World', 88, 'hello@example.com')";
 $connection->query($sql);

 // SELECT DATA
 $sql = "SELECT * FROM " . $tableName;
 $result = $connection->fetchAll($sql); 

 // UPDATE DATA
 $id = 1; // table row id to update
 $sql = "UPDATE " . $tableName . " SET name = 'Your Name', email = 'your-email@example.com' WHERE id = " . $id;
 $connection->query($sql);

 // DELETE DATA
 $id = 1; // table row id to delete
 $sql = "DELETE FROM " . $tableName . " WHERE id = " . $id;
 $connection->query($sql);
 

3) SELECT COM CONDICAO

 $id = 2;
 $fields = array('id', 'name');
 $sql = $connection->select()
                  ->from($tableName) // to select all fields
                  //->from($tableName, $fields) // to select some particular fields                  
                  ->where('id = ?', $id)
                  ->where('age > ?', 30); // adding WHERE condition with AND
 $result = $connection->fetchAll($sql);
 

4) MELHOR FORMA DE USAR JOIN:

 $id_clientela = 1;
 $fields = array('id', 'name');
 $sql = $connection->select()
                        ->from($tableName) // to select all fields
                        ->joinUsing('telefone_clientela', 'id_clientela')
                        ->where('clientela.id_clientela = ?', $id_clientela);
 $result = $connection->fetchAll($sql);
 

NOTA: Se quiser ver os resultados basta usar o comando: print_r($result);

NOTA2: CASO QUEIRA CRIAR AS TABELAS DO EXEMPLO:

'''Exemplo1''''

 CREATE TABLE IF NOT EXISTS `mytest` (
   `id` int(11) NOT NULL AUTO_INCREMENT,
   `name` varchar(100) NOT NULL,
   `age` tinyint(3) NOT NULL,
   `email` varchar(255) NOT NULL,
   PRIMARY KEY (`id`)
 ) ENGINE=InnoDB DEFAULT CHARSET=utf8 AUTO_INCREMENT=1 ;

'''Clientela e os telefones da clientela:'''

 CREATE TABLE IF NOT EXISTS `clientela` (
   `id_clientela` int(11) NOT NULL AUTO_INCREMENT,
   `nome` varchar(100) NOT NULL,
   `email` varchar(255) NOT NULL,
   PRIMARY KEY (`id_clientela`)
 ) ENGINE=InnoDB DEFAULT CHARSET=utf8 AUTO_INCREMENT=1 ;

 CREATE TABLE IF NOT EXISTS `telefone_clientela` (
   `id` int(11) NOT NULL AUTO_INCREMENT,
   `ddd` varchar(10) NOT NULL,
   `numero` varchar(20) NOT NULL,
   `id_clientela` int(11) NOT NULL,
   FOREIGN KEY (id_clientela) REFERENCES clientela(id_clientela),
   PRIMARY KEY (`id`)
 ) ENGINE=InnoDB DEFAULT CHARSET=utf8 AUTO_INCREMENT=1 ;