Magento 2 add custom column in product grid?

Thansk to @Dhrumin.

My working code here:

app/code/[Vendor]/[Module]/registration.php

<?php

\Magento\Framework\Component\ComponentRegistrar::register(
    \Magento\Framework\Component\ComponentRegistrar::MODULE,
    '[Vendor]_[Module]',
    __DIR__
);

app/code/[Vendor]/[Module]/etc/module.xml

<?xml version="1.0" ?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="../../../../../lib/internal/Magento/Framework/Module/etc/module.xsd">
    <module name="[Vendor]_[Module]" setup_version="0.0.1"/>
</config>

app/code/[Vendor]/[Module]/etc/di.xml

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">
    <preference for="Magento\Sales\Block\Adminhtml\Order\Create\Search\Grid" type="[Vendor]\[Module]\Block\Adminhtml\Order\Create\Search\Grid" />
</config>

app/code/[Vendor]/[Module]/Block/Adminhtml/Order/Create/Search/Grid.php

<?php

namespace [Vendor]\[Module]\Block\Adminhtml\Order\Create\Search;

class Grid extends \Magento\Sales\Block\Adminhtml\Order\Create\Search\Grid
{
    /**
     * Grid constructor.
     * @param \Magento\Backend\Block\Template\Context $context
     * @param \Magento\Backend\Helper\Data $backendHelper
     * @param \Magento\Catalog\Model\ProductFactory $productFactory
     * @param \Magento\Catalog\Model\Config $catalogConfig
     * @param \Magento\Backend\Model\Session\Quote $sessionQuote
     * @param \Magento\Sales\Model\Config $salesConfig
     * @param array $data
     */
    public function __construct(
        \Magento\Backend\Block\Template\Context $context,
        \Magento\Backend\Helper\Data $backendHelper,
        \Magento\Catalog\Model\ProductFactory $productFactory,
        \Magento\Catalog\Model\Config $catalogConfig,
        \Magento\Backend\Model\Session\Quote $sessionQuote,
        \Magento\Sales\Model\Config $salesConfig,
        array $data = []
    )
    {
        $this->_productFactory = $productFactory;
        $this->_catalogConfig = $catalogConfig;
        $this->_sessionQuote = $sessionQuote;
        $this->_salesConfig = $salesConfig;
        parent::__construct($context, $backendHelper, $productFactory, $catalogConfig, $sessionQuote, $salesConfig, $data);
    }

    /**
     * Prepare collection to be displayed in the grid
     *
     * @return $this
     */
    protected function _prepareCollection()
    {
        $attributes = $this->_catalogConfig->getProductAttributes();
        /* @var $collection \Magento\Catalog\Model\ResourceModel\Product\Collection */
        $collection = $this->_productFactory->create()->getCollection();
        $collection->setStore(
            $this->getStore()
        )->addAttributeToSelect(
            $attributes
        )->addAttributeToSelect(
            'sku'
        )->addStoreFilter()->addAttributeToFilter(
            'type_id',
            $this->_salesConfig->getAvailableProductTypes()
        )->addAttributeToSelect(
            'gift_message_available'
        );

        $collection->joinField(
            'barcode_qty',
            'cataloginventory_stock_item',
            'qty',
            'product_id=entity_id',
            '{{table}}.stock_id=1 AND {{table}}.website_id=0',
            'left'
        );

        $this->setCollection($collection);

        $p = get_parent_class($this);
        $pp = get_parent_class($p);
        return $pp::_prepareCollection();
    }

    /**
     * Prepare columns
     *
     * @return $this
     */
    protected function _prepareColumns()
    {
        $this->addColumn(
            'entity_id',
            [
                'header' => __('ID'),
                'sortable' => true,
                'header_css_class' => 'col-id',
                'column_css_class' => 'col-id',
                'index' => 'entity_id'
            ]
        );

        $this->addColumn(
            'barcode_qty',
            [
                'header' => __('Quantity'),
                'type' => 'number',
                'index' => 'barcode_qty'
            ]
        );

        $this->addColumn(
            'name',
            [
                'header' => __('Product'),
                'renderer' => \Magento\Sales\Block\Adminhtml\Order\Create\Search\Grid\Renderer\Product::class,
                'index' => 'name'
            ]
        );
        $this->addColumn('sku', ['header' => __('SKU'), 'index' => 'sku']);
        $this->addColumn(
            'price',
            [
                'header' => __('Price'),
                'column_css_class' => 'price',
                'type' => 'currency',
                'currency_code' => $this->getStore()->getCurrentCurrencyCode(),
                'rate' => $this->getStore()->getBaseCurrency()->getRate($this->getStore()->getCurrentCurrencyCode()),
                'index' => 'price',
                'renderer' => \Magento\Sales\Block\Adminhtml\Order\Create\Search\Grid\Renderer\Price::class
            ]
        );

        $this->addColumn(
            'in_products',
            [
                'header' => __('Select'),
                'type' => 'checkbox',
                'name' => 'in_products',
                'values' => $this->_getSelectedProducts(),
                'index' => 'entity_id',
                'sortable' => false,
                'header_css_class' => 'col-select',
                'column_css_class' => 'col-select'
            ]
        );

        $this->addColumn(
            'qty',
            [
                'filter' => false,
                'sortable' => false,
                'header' => __('Quantity'),
                'renderer' => \Magento\Sales\Block\Adminhtml\Order\Create\Search\Grid\Renderer\Qty::class,
                'name' => 'qty',
                'inline_css' => 'qty',
                'type' => 'input',
                'validate_class' => 'validate-number',
                'index' => 'qty'
            ]
        );

        $p = get_parent_class($this);
        $pp = get_parent_class($p);
        return $pp::_prepareColumns();
    }

}

Hope it helps.

Yes i find the solution for my question, open below file for path and override in your o custom module.

vendor/magento/module-sales/Block/Adminhtml/Order/Create/Search/Grid.php

And add below code in _prepareCollection() function,

$collection->joinField(
                'qty_in_stock',
                'cataloginventory_stock_item',
                'qty',
                'product_id=entity_id',
                '{{table}}.stock_id=1',
                'left'
        );

Now add below code in _prepareColumns function.

$this->addColumn(
                'qty_in_stock',
                [
                'header' => __('Quantity In Stock'),
                'type' => 'number',
                'index' => 'qty_in_stock'
                ]
        );

Hope it's help you.