Group by multiple years

Question

I have an application where I need to sum a field by year PLUS the the previous 2 years. When I sum simply by year, it looks like this:
select s.survey_year. sum(ac.plover_calculated_adult) AS totalCalcAdults
from dms.adult_census ac,dms.sites s
where ac.site_id = s.site_id
group by s.survey_year
How do I group by year plus the previous 2 years? I'm at a loss for how to write that.
Thanks in advance!!
JOhn

Answer 1

Hi,
It sounds like you want ot use RANGE BETWEEN in the analytic clause.
I don't have versions of your tables, so I'll illustrate using scott.emp:
SELECT       TRUNC (hiredate, 'YEAR')     AS hire_year
,       COUNT (*)                  AS cnt_1
,       SUM (COUNT (*)) OVER ( ORDER BY       TRUNC (hiredate, 'YEAR')
                                   RANGE BETWEEN     (2 * 366) PRECEDING
                           AND     CURRENT ROW
                      )        AS cnt_3
,       SUM (sal)               AS total_sal_1
,       SUM (SUM (sal)) OVER ( ORDER BY       TRUNC (hiredate, 'YEAR')
                                   RANGE BETWEEN     (2 * 366) PRECEDING
                           AND     CURRENT ROW
                      )        AS total_sal_3
FROM       scott.emp
GROUP BY  TRUNC (hiredate, 'YEAR')
ORDER BY  hire_year
;Output:
HIRE_YEAR      CNT_1      CNT_3 TOTAL_SAL_1 TOTAL_SAL_3
01-JAN-80          1          1         800         800
01-JAN-81         10         11       22825       23625
01-JAN-82          1         12        1300       24925
01-JAN-87          2          2        4100        4100As you can see, the cnt_3 and total_sal_3 columns are the totals of the cnt_1 and total_sal_1 columns for the last 3 years , which may mean the last 1, 2 or 3 rows , depending on what years are in the table.
If survery_year is a NUMBER, then you'll probably want to use "RANGE BETWEEN 2 PRECEDING AND CURRENT ROW".
I hope that answers your question.
If not, post a little sample data (CREATE TABLE and INSERT statements) and the resutls you want from that data.