simplified 'HAVING' clause

exercise 5.sql

@@ -6,5 +6,5 @@ SELECT DISTINCT
 FROM general_ledger_accounts g JOIN invoice_line_items i JOIN invoices n
 	ON g.account_number = i.account_number AND i.invoice_id = n.invoice_id
 GROUP BY g.account_description
-HAVING n.invoice_date >= '2018-04-01' AND n.invoice_date <= '2018-06-30'
+HAVING n.invoice_date BETWEEN '2018-04-01' AND '2018-06-30'
 ORDER BY line_item_amount_sum DESC;