Arranging by months_total query

hello , in my senario, students can make entries in the database whole year round entering the number of cash they spent on diferent items.

basically the table is like this

id,timestamp,username,itembought,price

and some sample data is

2, 2014-01-20 13:55:31 , raj, piza, 50
3, 2014-01-21 14:53:32 , raj, juice, 10
4, 2014-01-21 11:52:33 , rita, rice, 150
5, 2014-02-21 11:51:34 , raj, noodle, 250

.
.
.

5000, 2015-01-12 17:50:38 , rani, fish, 40

now i need a yearly report for each student per months(total)

something like this

2014
        january   february    ... december   total
raj     150     100                   100                   2500
rita     150    200                   28                       3000
rani    100  200                     200                  2580    

how can i write my query to get this ? or any suggestion to achive this?

$query = $this->db->query("

select groups.id,groups.groupname,
sum(if( MONTH(timestamp) = 1, price, 0 )) as January,
sum(if( MONTH(timestamp) = 2, price, 0 )) as February,
sum(if( MONTH(timestamp) = 3, price, 0 )) as March,
sum(if( MONTH(timestamp) = 4, price, 0 )) as April,
sum(if( MONTH(timestamp) = 5, price, 0 )) as May,
sum(if( MONTH(timestamp) = 6, price, 0 )) as June,
sum(if( MONTH(timestamp) = 7, price, 0 )) as July,
sum(if( MONTH(timestamp) = 8, price, 0 )) as August,
sum(if( MONTH(timestamp) = 9, price, 0 )) as September,
sum(if( MONTH(timestamp) = 10, price, 0 )) as October,
sum(if( MONTH(timestamp)=11, price, 0 )) as November,
sum(if( MONTH(timestamp) = 12, price, 0 )) as December,
sum(price) as Total
from groups left join purchase on groups.id = purchase .usergroup
where (YEAR(timestamp) ='$year')
group by groups.id,
groups.groupname



");

i had to slightly modify the structure of the table
where i include group which has the name and id of student

and purchase table is like this
2, 2014-01-20 13:55:31 , 1, piza, 50
3, 2014-01-21 14:53:32 , 2, juice, 10
4, 2014-01-21 11:52:33 , 1, rice, 150
5, 2014-02-21 11:51:34 , 1, noodle, 250

instead of the name

the solution works but it is not very neat, is there a code igniter way to do this?