diff --git a/invoices-per-country.sql b/invoices-per-country.sql
index d094854..75a88e2 100644
--- a/invoices-per-country.sql
+++ b/invoices-per-country.sql
@@ -1,5 +1,7 @@
-SELECT co.country_name, count(*), AVG(i.total_price)
-FROM country co, city ci, customer cu, invoice i
-WHERE co.id = ci.country_id AND ci.id = cu.city_id AND cu.id = i.customer_id
-GROUP BY co.country name
-HAVING AVG(i.total_price) > (SELECT AVG(total price))
+SELECT co.country_name, COUNT(*) AS invoice_count, AVG(i.total_price) AS avg_total_price
+FROM country co
+INNER JOIN city ci ON co.id = ci.country_id
+INNER JOIN customer cu ON ci.id = cu.city_id
+INNER JOIN invoice i ON cu.id = i.customer_id
+GROUP BY co.country_name
+HAVING AVG(i.total_price) > (SELECT AVG(total_price) FROM invoice);