create function countnulls("any") returns int language 'c' IMMUTABLE as 'countnulls', 'count_nulls';
create function countnulls("any", "any") returns int language 'c' IMMUTABLE as 'countnulls', 'count_nulls';
create function countnulls("any", "any", "any") returns int language 'c' IMMUTABLE as 'countnulls', 'count_nulls';
create function countnulls("any", "any", "any", "any") returns int language 'c' IMMUTABLE as 'countnulls', 'count_nulls';
create function countnulls("any", "any", "any", "any", "any") returns int language 'c' IMMUTABLE as 'countnulls', 'count_nulls';
create function countnulls("any", "any", "any", "any", "any", "any") returns int language 'c' IMMUTABLE as 'countnulls', 'count_nulls';
create function countnulls("any", "any", "any", "any", "any", "any", "any") returns int language 'c' IMMUTABLE as 'countnulls', 'count_nulls';
create function countnulls("any", "any", "any", "any", "any", "any", "any", "any") returns int language 'c' IMMUTABLE as 'countnulls', 'count_nulls';

-- only available in 8.4 or above
-- create or replace function countnulls(VARIADIC "any") returns int language 'c' IMMUTABLE as 'countnulls', 'count_nulls';