<?php
require('../../../wp-load.php');
global $wpdb;

$file = 'updatequantity.csv';
$handle = fopen($file, "r");
fgetcsv($handle,1000,",");// remove first row/header file must have a header to not lose the first row of data

while(($fileop = fgetcsv($handle,1000,",")) !==false)
{
// gets the correct columns
$sku = $fileop[0];
$quantity = $fileop[1];
// gets the product id so we can later update where id =...
$product_id = $wpdb->get_var( $wpdb->prepare( "SELECT post_id FROM $wpdb->postmeta WHERE meta_key='_sku' AND meta_value='%s' LIMIT 1", $sku ) );

if ($product_id != '') {
    // Update meta
    update_post_meta( $product_id, '_stock', $quantity );
    // Clear total stock transient
    delete_transient( 'wc_product_total_stock_' . $product_id );
}
else{
    echo "No Id Found for SKU: $sku</br>";
}
}
echo "Stock Quantity Updated</br>";
?>