To get all the products with no categories, use the following code in WooCommerce:

/******Start of the code******/

<?php
include ‘wp-load.php’;
global $wpdb;
$srNo = 1;
$productWithNoCatsArr = array();
$productIdsResults = $wpdb->get_results(“SELECT ID, post_title, post_modified, meta_value as sku FROM ” . $wpdb->prefix . “posts as wp left join ” . $wpdb->prefix . “postmeta as wpm on wp.ID = wpm.post_id WHERE post_status=’publish’ AND post_type=’product’ AND wpm.meta_key=’_sku'”, ARRAY_A);

foreach ($productIdsResults as $productId) {
$prodId = $productId[‘ID’];
$product_cats = wp_get_post_terms($prodId, ‘product_cat’, array(“fields” => “ids”));
if (0 == count($product_cats)) {
$productWithNoCatsArr[$prodId][‘id’] = $prodId;
$productWithNoCatsArr[$prodId][‘name’] = $productId[‘post_title’];
$productWithNoCatsArr[$prodId][‘sku’] = $productId[‘sku’];
$productWithNoCatsArr[$prodId][‘last_updated’] = $productId[‘post_modified’];
}
}
?>

<h1 class=”wp-heading-inline”><?php echo esc_html(‘Products With No Categories’); ?></h1>
<hr class=”wp-header-end”><br>
<table id=”products_with_no_categories” cellpadding=”5″ cellspacing=”5″ width=”100%”>
<thead>
<tr>
<th width=”3%” style=”text-align:center”>Sr. No.</th>
<th width=”9%” style=”text-align:center”>Product ID</th>
<th width=”15%”>SKU</th>
<th width=”31%”>Product Name</th>
</tr>
</thead>
<tbody>
<?php
if (count($productWithNoCatsArr) > 0) {
foreach ($productWithNoCatsArr as $row) {
$entityID = $row[‘id’];
$prdName = $row[‘name’];
$sku = $row[‘sku’];
?>
<tr>
<td style=”text-align:center”><?php echo $srNo; ?></td>
<td style=”text-align:center”><?php echo $entityID; ?></td>
<td style=”text-align:center”><?php echo $sku; ?></td>
<td><?php echo $prdName; ?></td>
</tr>
<?php
$srNo++;
}
}
?>
</tbody>
</table>

/******End of the code******/

That’s it you are done!