I have records related to dates:
DATE AMOUNT
16.03.2013 3
16.03.2013 4
16.03.2013 1
16.03.2013 3
17.03.2013 4
17.03.2014 3
I know how to sum them up for each day, but how could I sum them up by week?`
Try this
SELECT to_char(DATE - 7/24,'IYYY'), to_char(DATE - 7/24,'IW'),SUM(AMOUNT)
FROM YourTable
GROUP BY to_char(DATE - 7/24,'IYYY'), to_char(DATE - 7/24,'IW')
Output would be:
+-----+-------+--------+
|YEAR | WEEK | AMOUNT |
+-----+-------+--------+
|2013 | 11 | 18 |
|2013 | 13 | 3 |
+-----+-------+--------+