Return two values for one site in single query

Question

Oracle 10g on Solaris 10
data:
value integer
date timestamp
This query works as is:
WITH vals AS
     (SELECT start_date_time,
          value
     FROM     r_base a,
          hdb_site_datatype b,
          hdb_site c,
          hdb_datatype d
     WHERE     a.site_datatype_id = b.site_datatype_id
     AND     a.interval = 'day'
     AND     b.site_id = c.site_id
     AND     c.site_common_name = 'CABALLO'
     AND     b.datatype_id = d.datatype_id
     AND     d.datatype_common_name = 'pool elevation'
     AND     a.start_date_time > a.start_date_time - 367)
     SELECT x.start_date_time,
          x.VALUE,
          y.start_date_time,
          y.VALUE AS valuem1w,
          z.start_date_time,
          z.VALUE AS valuem1dm1y
     FROM     vals x,
          vals y,
          vals z
     WHERE     y.start_date_time(+) = x.start_date_time - 7
     AND     z.start_date_time(+) = ADD_MONTHS (x.start_date_time-1,-12)
     AND     x.start_date_time = TO_DATE('07-JAN-2008','DD-MON-YYYY');
and this query works:
WITH vals AS
     (SELECT start_date_time,
          value
     FROM     r_base a,
          hdb_site_datatype b,
          hdb_site c,
          hdb_datatype d
     WHERE     a.site_datatype_id = b.site_datatype_id
     AND     a.interval = 'day'
     AND     b.site_id = c.site_id
     AND     c.site_common_name = 'CABALLO'
     AND     b.datatype_id = d.datatype_id
     AND     d.datatype_common_name = 'storage'
     AND     a.start_date_time > a.start_date_time - 367)
     SELECT x.start_date_time,
          x.VALUE,
          y.start_date_time,
          y.VALUE AS valuem1w,
          z.start_date_time,
          z.VALUE AS valuem1dm1y
     FROM     vals x,
          vals y,
          vals z
     WHERE     y.start_date_time(+) = x.start_date_time - 7
     AND     z.start_date_time(+) = ADD_MONTHS (x.start_date_time-1,-12)
     AND     x.start_date_time = TO_DATE('07-JAN-2008','DD-MON-YYYY');
I need it to return storage and pool elevation in a single query instead of two queries.
The results should be:
current day, elevation_value; current day minus 1 week, elevation_value; current day minus 1 day minus 1 year, elevation_value; current day, storage_value; current day minus 1 week, storage_value; current day minus 1 day minus 1 year, storage_value
Thanks
Very, very much appreciate if you can show me how to do this..

Answer 1

something like this, perhaps? (untested, as I don't have your data):
WITH date_param as (select TO_DATE('07-JAN-2008','DD-MON-YYYY') p_date from dual),
SELECT max(nvl(case when d.datatype_common_name = 'pool elevation'
                         and a.start_date_time = p_date then value
               end)) elevation_curr_day_val,
       max(nvl(case when d.datatype_common_name = 'pool elevation'
                         and a.start_date_time = p_date-7 then value
               end)) elevation_last_week_val,
       max(nvl(case when d.datatype_common_name = 'pool elevation'
                         and a.start_date_time = add_months(p_date-1, -12) then value
               end)) elevation_last_year_val,
       max(nvl(case when d.datatype_common_name = 'storage'
                         and a.start_date_time = p_date then value
               end)) storage_curr_day_val,
       max(nvl(case when d.datatype_common_name = 'storage'
                         and a.start_date_time = p_date-7 then value
               end)) storage_last_week_val,
       max(nvl(case when d.datatype_common_name = 'storage'
                         and a.start_date_time = add_months(p_date-1, -12) then value
               end)) storage_last_year_val
FROM r_base a,
      hdb_site_datatype b,
      hdb_site c,
      hdb_datatype d
WHERE a.site_datatype_id = b.site_datatype_id
AND a.interval = 'day'
AND b.site_id = c.site_id
AND c.site_common_name = 'CABALLO'
AND b.datatype_id = d.datatype_id
AND d.datatype_common_name in ('pool elevation', 'storage')
AND a.start_date_time in (p_date, p_date-7, add_months(p_date-1, -12));