Hi!
I have a problem with a query in Mysql.
In my table stored access for period.

My table cloumns are
-account_id (primaty key)
-years (primaty key)
-month (primaty key)
-access_number

account_id_A 2012 03 12
account_id_A 2012 04 15
account_id_A 2013 04 10
account_id_B 2012 03 12
account_id_B 2012 04 15
account_id_B 2013 03 7

I need to create a query to extract:
account_id, total number of access in 2012, total number of access in 2013.
I'm unable to prepare query in a correct way.
thanks!