diff --git a/includes/api/class-wc-rest-coupons-controller.php b/includes/api/class-wc-rest-coupons-controller.php
index 3fbd1df064e..dfd1103d438 100644
--- a/includes/api/class-wc-rest-coupons-controller.php
+++ b/includes/api/class-wc-rest-coupons-controller.php
@@ -207,7 +207,7 @@ class WC_REST_Coupons_Controller extends WC_REST_Posts_Controller {
 
 		// ID.
 		if ( isset( $request['id'] ) ) {
-			$code     = $wpdb->get_var( $wpdb->prepare( "SELECT post_title FROM $wpdb->posts WHERE id = %s AND post_type = 'shop_coupon' AND post_status = 'publish'", $request['id'] ) );
+			$code     = $wpdb->get_var( $wpdb->prepare( "SELECT post_title FROM $wpdb->posts WHERE id = %d AND post_type = 'shop_coupon' AND post_status = 'publish'", $request['id'] ) );
 			$coupon   = new WC_Coupon( $code );
 		} else {
 			$coupon   = new WC_Coupon();