consulta para resumen mensual

[[gluglu]]

Código SQL [-]
CREATE TABLE DIAS (
    DIA INTEGER);

INSERT INTO DIAS (DIA)
          VALUES (1);
INSERT INTO DIAS (DIA)
          VALUES (2);
INSERT INTO DIAS (DIA)
          VALUES (3);
INSERT INTO DIAS (DIA)
          VALUES (4);
INSERT INTO DIAS (DIA)
          VALUES (5);
INSERT INTO DIAS (DIA)
          VALUES (6);
INSERT INTO DIAS (DIA)
          VALUES (7);
INSERT INTO DIAS (DIA)
          VALUES (8);
INSERT INTO DIAS (DIA)
          VALUES (9);
INSERT INTO DIAS (DIA)
          VALUES (10);
COMMIT WORK;

CREATE TABLE RECEPCION (
    FECHA DATE,
    KGS INTEGER);
 
INSERT INTO RECEPCION (FECHA, KGS)
               VALUES ('2011-01-01', 1);
INSERT INTO RECEPCION (FECHA, KGS)
               VALUES ('2011-01-01', 1);
INSERT INTO RECEPCION (FECHA, KGS)
               VALUES ('2011-01-02', 3);
INSERT INTO RECEPCION (FECHA, KGS)
               VALUES ('2011-01-04', 4);
INSERT INTO RECEPCION (FECHA, KGS)
               VALUES ('2011-01-04', 4);
INSERT INTO RECEPCION (FECHA, KGS)
               VALUES ('2011-01-06', 6);
INSERT INTO RECEPCION (FECHA, KGS)
               VALUES ('2011-01-06', 6);
INSERT INTO RECEPCION (FECHA, KGS)
               VALUES ('2011-01-08', 8);
INSERT INTO RECEPCION (FECHA, KGS)
               VALUES ('2011-01-09', 9);
COMMIT WORK;

Aplico :

Código Delphi [-]
Select D.DIA, RM.SUMA from Dias D
left join (Select extract(day from fecha) as dia,
                  sum(kgs) as suma
           from Recepcion
           group by dia ) as RM
  on D.DIA = RM.DIA

y el resultado que obtengo es :

Código SQL [-]
DIA SUMA
  1    2
  2    3
  3    Null
  4    8
  5    Null
  6    12
  7    Null
  8    8
  9    9
 10    Null