diff --git a/invoices-per-country.sql b/invoices-per-country.sql
index d094854..4107f36 100644
--- a/invoices-per-country.sql
+++ b/invoices-per-country.sql
@@ -1,5 +1,16 @@
-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 customer_count, 
+    AVG(i.total_price) AS avg_total_price
+FROM 
+    country co
+JOIN 
+    city ci ON co.id = ci.country_id
+JOIN 
+    customer cu ON ci.id = cu.city_id
+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);