InstallData.php

<?php
/**
 * Copyright © 2018 . All rights reserved.
 */

namespace Test\Test\Setup;
use Magento\Customer\Model\Customer;
use Magento\Customer\Setup\CustomerSetupFactory;
use Magento\Eav\Model\Entity\Attribute\SetFactory as AttributeSetFactory;
use Magento\Framework\Setup\InstallDataInterface;
use Magento\Framework\Setup\ModuleContextInterface;
use Magento\Framework\Setup\ModuleDataSetupInterface;

/**
 * @codeCoverageIgnore
 */
class InstallData implements InstallDataInterface
{

    /**
     * @var CustomerSetupFactory
     */
    protected $customerSetupFactory;

    /**
     * @var AttributeSetFactory
     */
    private $attributeSetFactory;

    /**
     * @param CustomerSetupFactory $customerSetupFactory
     * @param AttributeSetFactory $attributeSetFactory
     */
    public function __construct(
        CustomerSetupFactory $customerSetupFactory,
        AttributeSetFactory $attributeSetFactory
    ) {
        $this->customerSetupFactory = $customerSetupFactory;
        $this->attributeSetFactory = $attributeSetFactory;
    }


    public function install(ModuleDataSetupInterface $setup, ModuleContextInterface $context)
    {
        /** @var CustomerSetup $customerSetup */
        $customerSetup = $this->customerSetupFactory->create(['setup' => $setup]);


        $customerEntity = $customerSetup->getEavConfig()->getEntityType('customer');
        $attributeSetId = $customerEntity->getDefaultAttributeSetId();

        /** @var $attributeSet AttributeSet */
        $attributeSet = $this->attributeSetFactory->create();
        $attributeGroupId = $attributeSet->getDefaultGroupId($attributeSetId);

        // Add club start date
        $customerSetup->addAttribute(
            Customer::ENTITY,
            'club_start_date',
            [
                'type' => 'datetime',
                'label' => 'Club start date',
                'input' => 'date',
                'required' => false,
                'backend' => \Magento\Eav\Model\Entity\Attribute\Backend\Datetime::class,
                'frontend' => \Magento\Eav\Model\Entity\Attribute\Frontend\Datetime::class,
                'sort_order' => 900,
                'visible' => true,
                'system' => false,
                'input_filter' => 'date',
                'validate_rules' => '{"input_validation":"date"}',
                'position' => 90,
                'is_used_in_grid' => true,
                'is_visible_in_grid' => true,
                'is_filterable_in_grid' => true,
                'is_searchable_in_grid' => true
            ]
        );

        /** @var  $attribute */
        $attribute = $customerSetup->getEavConfig()->getAttribute('customer', 'club_start_date');
        $attribute->addData([
            'used_in_forms', ['adminhtml_customer'],
            'attribute_group_id' => $attributeGroupId,
            'attribute_set_id' => $attributeSetId
        ]);
        $attribute->save();

        // Add club end date
        $customerSetup->addAttribute(
            Customer::ENTITY,
            'club_end_date',
            [
                'type' => 'datetime',
                'label' => 'Club end date',
                'input' => 'date',
                'required' => false,
                'backend' => \Magento\Eav\Model\Entity\Attribute\Backend\Datetime::class,
                'frontend' => \Magento\Eav\Model\Entity\Attribute\Frontend\Datetime::class,
                'sort_order' => 900,
                'visible' => true,
                'system' => false,
                'input_filter' => 'date',
                'validate_rules' => '{"input_validation":"date"}',
                'position' => 90,
                'is_used_in_grid' => true,
                'is_visible_in_grid' => true,
                'is_filterable_in_grid' => true,
                'is_searchable_in_grid' => true
            ]
        );

        /** @var  $attribute */
        $attribute = $customerSetup->getEavConfig()->getAttribute('customer', 'club_end_date');
        $attribute->addData([
            'used_in_forms', ['adminhtml_customer'],
            'attribute_group_id' => $attributeGroupId,
            'attribute_set_id' => $attributeSetId
        ]);

        $setup->getConnection()->addColumn(
            $setup->getTable('customer_entity'),
            'club_end_date',
            [
                'type'     => \Magento\Framework\DB\Ddl\Table::TYPE_DATE,
                'nullable' => true,
                'comment'  => 'Club end Date',
            ]
        );
        $setup->getConnection()->addColumn(
            $setup->getTable('customer_entity'),
            'club_start_date',
            [
                'type'     => \Magento\Framework\DB\Ddl\Table::TYPE_DATE,
                'nullable' => true,
                'comment'  => 'Club Start Date',
            ]
        );


        $attribute->save();
    }
}