How would i go about this query

Question

I need to sum 3 of the same volume fields based on 3 diff where in clauses. in one single query. So basicaly these three queries below in one query. Its been a long time since ive had to do queries, can any also link me to a good resource for understanding nested selects, unions etc..
SELECT A.DAYTIME,
SUM(A.GRS_VOL_GAS_SE3M3) AS SWEET_FUEL_CONS
FROM
RV_STRM_DAY_STREAM_MEAS_GAS A
WHERE
A.CODE IN ('M_2370', 'M_8251','M_GYCOL')
AND A.DAYTIME >= TO_DATE('01-Jan-2006')
AND A.DAYTIME <= TO_DATE('31-Jan-2006')
GROUP BY A.DAYTIME
ORDER BY A.DAYTIME
SELECT A.DAYTIME,
SUM(A.GRS_VOL_GAS_SE3M3) AS SOUR_FUEL_CONS
FROM
RV_STRM_DAY_STREAM_MEAS_GAS A
WHERE
A.CODE IN ('M_1370A', M_1370B','M_1370C','M_1370D', M_1370E','M_1370F')
AND A.DAYTIME >= TO_DATE('01-Jan-2006')
AND A.DAYTIME <= TO_DATE('31-Jan-2006')
GROUP BY A.DAYTIME
ORDER BY A.DAYTIME
SELECT A.DAYTIME,
SUM(A.GRS_VOL_GAS_SE3M3) AS Flare
FROM
RV_STRM_DAY_STREAM_MEAS_GAS A
WHERE
A.CODE IN ('M_8300')
AND A.DAYTIME >= TO_DATE('01-Jan-2006')
AND A.DAYTIME <= TO_DATE('31-Jan-2006')
GROUP BY A.DAYTIME
ORDER BY A.DAYTIME

Answer 1

not sure if this is what you are looking for:
Select a1.daytime,
       sum(a1.sweet_fuel_cons) sweet_fuel_cons,
       sum(a1.sour_fuel_cons)  sour_fuel_cons,
       sum(a1.flare)           flare
  From (SELECT A.DAYTIME,
               SUM(A.GRS_VOL_GAS_SE3M3) AS SWEET_FUEL_CONS,
               0 SOUR_FUEL_CONS,
               0 Flare
          FROM RV_STRM_DAY_STREAM_MEAS_GAS A
         WHERE A.CODE IN ('M_2370', 'M_8251','M_GYCOL')
           AND A.DAYTIME >= TO_DATE('01-Jan-2006','dd-mon-yyyy')
           AND A.DAYTIME <= TO_DATE('31-Jan-2006','dd-mon-yyyy')
        GROUP BY A.DAYTIME
        UNION
        SELECT A.DAYTIME,
               0 SWEET_FUEL_CONS,
               SUM(A.GRS_VOL_GAS_SE3M3) AS SOUR_FUEL_CONS,
               0 Flare
          FROM RV_STRM_DAY_STREAM_MEAS_GAS A
         WHERE A.CODE IN ('M_1370A', M_1370B','M_1370C','M_1370D', M_1370E','M_1370F')
           AND A.DAYTIME >= TO_DATE('01-Jan-2006','dd-mon-yyyy')
           AND A.DAYTIME <= TO_DATE('31-Jan-2006','dd-mon-yyyy')
        GROUP BY A.DAYTIME
        UNION
        SELECT A.DAYTIME,
               0 SWEET_FUEL_CONS,
               0 SOUR_FUEL_CONS,
               SUM(A.GRS_VOL_GAS_SE3M3) AS Flare
          FROM RV_STRM_DAY_STREAM_MEAS_GAS A
         WHERE A.CODE IN ('M_8300')
           AND A.DAYTIME >= TO_DATE('01-Jan-2006','dd-mon-yyyy')
           AND A.DAYTIME <= TO_DATE('31-Jan-2006','dd-mon-yyyy')
        GROUP BY A.DAYTIME) a1
Group by a1.daytime;