SQL needed: sum over values by month

Question

i have an table with values like this:

count1   count2  count3  month
12        1       4       01/12/2011
6         5       4       23/12/2011
14                 


        

Answer 1

SELECT
SUM(count1) as sum_count1,
to_char(month, 'yyyy-MM') as month
FROM
dataframe 
GROUP BY
month