SELECT i.billing_country AS country, COUNT(i.total) AS total_invoice, COUNT(DISTINCT c.customer_id) AS total_customer FROM invoice AS i LEFT OUTER JOIN client AS c ON c.customer_id = i.customer_id WHERE EXTRACT(YEAR FROM CAST(invoice_date AS timestamp)) IN (SELECT EXTRACT(YEAR FROM CAST(invoice_date AS timestamp)) FROM invoice WHERE EXTRACT(MONTH FROM CAST(invoice_date AS timestamp)) IN (6,7,8) GROUP BY EXTRACT(YEAR FROM CAST(invoice_date AS timestamp)) ORDER BY SUM(total) DESC LIMIT 1) GROUP BY i.billing_country ORDER BY total_invoice DESC, country;