diff --git a/classes/tax/TaxRulesTaxManager.php b/classes/tax/TaxRulesTaxManager.php
index 6d728eda0..74ca44165 100644
--- a/classes/tax/TaxRulesTaxManager.php
+++ b/classes/tax/TaxRulesTaxManager.php
@@ -69,7 +69,7 @@ class TaxRulesTaxManagerCore implements TaxManagerInterface
 		WHERE `id_country` = '.(int)$this->address->id_country.'
 		AND `id_tax_rules_group` = '.(int)$this->type.'
 		AND `id_state` IN (0, '.(int)$this->address->id_state.')
-		AND ('.pSQL($postcode).' BETWEEN `zipcode_from` AND `zipcode_to` OR `zipcode_from` = 0 OR `zipcode_from` = '.pSQL($postcode).')
+		AND (\''.pSQL($postcode).'\' BETWEEN `zipcode_from` AND `zipcode_to` OR `zipcode_from` = 0 OR `zipcode_from` = \''.pSQL($postcode).'\')
 		ORDER BY `zipcode_from` DESC, `zipcode_to` DESC, `id_state` DESC, `id_country` DESC');
 
 		$behavior = 0;