--
-- acs_util__boolean_query/2
--
create or replace function acs_util__boolean_query(
  character varying,
  boolean
) returns bool as $$

declare
  query_in		alias for $1;
  not_flag_in		alias for $2;
  v_sql_query		varchar;
  v_row_count		integer;
begin
  v_sql_query := 'select 1 where ';

  if not_flag_in then
    v_sql_query := v_sql_query || 'not ';
  end if;

  execute v_sql_query || 'exists (' || query_in || ')';

  get diagnostics v_row_count = ROW_COUNT;

  if v_row_count = 1 then
    return 't';
  else
    return 'f';
  end if;

end;$$ language plpgsql;