SQL & PL/SQL :: Grouping Totals By Date Ranges

I have to get totals from a table using different criteria, which I do like this:

<QUERY>
SELECT DISTINCT
SUM(CASE WHEN MYCONDITION1 THEN 1 ELSE 0 END) AS TOTAL1,
SUM(CASE WHEN MYCONDITION2 THEN 1 ELSE 0 END) AS TOTAL2
FROM TABLE1, TABLE2
WHERE COMMON_CONDITION1 AND COMMON_CONDITION2
AND datevalue1 >= DATE1 AND datevalue1 <= DATE2;
<QUERY>

This works fine and I get the intended result.Now, I have to repeat this for every week for the last 12 months, excluding holidays period. So, I generate a set of date ranges which will be used in the queries. So, I repeat the above sql statement for all the date ranges, which is a lengthy process.How can I do that in a single shot and get all totals for each date range.