Get Woocommerce productid by sku
<?php
/**
* get_product_id_by_sku
* @param string $sku product sku
* @return mixed product id when product found else null
*/
function get_product_id_by_sku( $sku ) {
global $wpdb;
$product_id = $wpdb->get_var(
$wpdb->prepare(
"SELECT post_id
FROM $wpdb->postmeta
WHERE meta_key='_sku'
AND meta_value='%s'
LIMIT 1",
$sku
)
);
return ( $product_id )? $product_id : null;
}