Consulta Sql que liste do 1º ao último dia do mes atual

  SELECT * 
  FROM generate_series(date_trunc('month',current_date), 
                      date_trunc('month',current_date) + INTERVAL'1 month' - INTERVAL'1 day',
                      INTERVAL'1 day');

     SELECT * 
    FROM generate_series(DATE'2012-12-01',DATE'2012-12-31',INTERVAL'1 day');
 

set term ^ ;
EXECUTE BLOCK
RETURNS (
  D DATE
)
AS
DECLARE VARIABLE DATAI DATE;
DECLARE VARIABLE DATAF DATE;
BEGIN
     DATAI = (SELECT DATEADD(1 - EXTRACT(DAY FROM CURRENT_DATE) DAY TO CURRENT_DATE ) FROM RDB$DATABASE);
     DATAF = (SELECT DATEADD(-EXTRACT(DAY FROM DATEADD(1 MONTH TO CURRENT_DATE )) DAY TO DATEADD(1 MONTH TO CURRENT_DATE)) FROM RDB$DATABASE);
     D = DATAI;

     WHILE (D <= DATAF) DO
       BEGIN
         --COLOCAR O SELECT AQUI
         SUSPEND;

         D = D + 1;
       END
END^