returns null on null input current_timestamp characteristics current_catalog current_schema localtimestamp authorization configuration xmlattributes concurrently current_date current_role current_time current_user nocreaterole nocreateuser serializable session_user xmlserialize constraints nulls first constraints insensitive lancompiler nosuperuser uncommitted unencrypted conversion privileges tablespace constraint references nulls last assignment asymmetric connection constraint conversion createrole createuser deferrable delimiters dictionary lc_collate nocreatedb privileges procedural references repeatable standalone statistics tablespace whitespace xmlelement aggregate collation extension including no action immutable aggregate assertion committed delimiter encrypted excluding exclusive following immediate immutable including increment initially isolation localtime noinherit partition preceding precision procedure statement superuser symmetric temporary unbounded validator xmlconcat xmlforest database function language operator sequence not null defaults inherits set null restrict volatile distinct absolute backward cascaded continue createdb database defaults deferred distinct document encoding external function identity implicit inherits language lc_ctype location maxvalue minvalue national operator overlaps password position prepared preserve reassign relative restrict security sequence template trailing variadic volatile xmlparse default foreign wrapper trigger mapping primary cascade returns plpgsql extract analyse between cascade catalog collate content current default definer disable extract foreign forward granted handler indexes inherit invoker leading mapping natural nologin nothing notnull numeric options overlay partial placing primary recheck release replica restart returns session similar storage trigger trusted unknown verbose version without wrapper xmlroot domain object family schema server unique stable strict offset access action always called column cursor domain double enable escape family freeze global header isnull minute nowait object offset option parser rename return revoke schema scroll search second server simple stable stdout strict system unique window table group index large class limit check abort admin cache chain check class cross cycle FALSE fetch first force group ilike index inner inout input large level limit local login match month names nulls order outer owned owner plans prior quote range reset right setof share start stdin strip sysid table treat until valid value while write xmlpi data role type user null like only desc both cast cost data desc each full hold hour last left like mode name next none null oids only over read role rows show temp TRUE type user view work year zone key add sql asc new old add and asc csv day dec key new not off old out row yes as on to as at by is no of on or to