Sum over values by month in milliseconds

Question

I have table with Values and Date. Values in Integer and date is Integer in milliseconds from 1970's... I need to get sum(value) for each month and i haven't any idea how to do it with date in milliseconds. Is it possible? Thanks.

My table "entry"

amount    |   date    
----------------------------
300       |   1390075200000
150       |   1390132500000
20        |   1391075200000
...       |   .............

What i want to get:

01.2014  |  450
02.2014  |  20
....

Answer 1

You have to convert the dates into a format supported by SQLite so that you can extract the month:

SELECT strftime('%Y-%m', date / 1000, 'unixepoch') AS month,
       SUM(value) AS sum
FROM entry
GROUP BY 1