fix: date condition in tax rule
diff --git a/erpnext/accounts/doctype/tax_rule/tax_rule.py b/erpnext/accounts/doctype/tax_rule/tax_rule.py
index 27b78e9..5bfca96 100644
--- a/erpnext/accounts/doctype/tax_rule/tax_rule.py
+++ b/erpnext/accounts/doctype/tax_rule/tax_rule.py
@@ -163,10 +163,15 @@
 def get_tax_template(posting_date, args):
 	"""Get matching tax rule"""
 	args = frappe._dict(args)
+	from_date = to_date = posting_date
+	if not posting_date:
+		from_date = "1900-01-01"
+		to_date = "4000-01-01"
+
 	conditions = [
 		"""(from_date is null or from_date <= '{0}')
-		and (to_date is null or to_date >= '{0}')""".format(
-			posting_date
+		and (to_date is null or to_date >= '{1}')""".format(
+			from_date, to_date
 		)
 	]