diff --git a/etc/schema/pgsql.schema.sql b/etc/schema/pgsql.schema.sql
index 7f28c5d81..56117d4f8 100644
--- a/etc/schema/pgsql.schema.sql
+++ b/etc/schema/pgsql.schema.sql
@@ -1,5 +1,9 @@
 /* Icinga Web 2 | (c) 2013-2015 Icinga Development Team | GPLv2+ */
 
+CREATE OR REPLACE FUNCTION unix_timestamp(timestamp with time zone) RETURNS bigint AS '
+        SELECT EXTRACT(EPOCH FROM $1)::bigint AS result
+' LANGUAGE sql;
+
 CREATE TABLE "icingaweb_group" (
   "id"     serial,
   "name"   character varying(64) NOT NULL,