Find duplicate arrays and sum another in array

Find duplicate arrays and sum another in array

sorry for my english ...
I use loop while and make array in $results. My array looks like this:
[0] => Array
(
[id] => 1
[data] => 2013-09-05
[Gabinet] => gabinet1
[a] => 0
[b] => 1
[c] => 0
)
[1] => Array
(
[id] => 2
[data] => 2013-09-05
[Gabinet] => gabinet2
[a] => 0
[b] => 0
[c] => 19
)
[2] => Array
(
[id] => 3
[data] => 2013-09-04
[Gabinet] => gabinet1
[a] => 9
[b] => 0
[c] => 1
)
[3] => Array
(
[id] => 4
[data] => 2013-09-04
[Gabinet] => gabinet2
[a] => 0
[b] => 2
[c] => 3
)
And how i can change this arrays to this:
[0] => Array
(
[Gabinet] => gabinet1
[a] => 9
[b] => 1
[c] => 1
)
[1] => Array
(
[Gabinet] => gabinet2
[a] => 0
[b] => 2
[c] => 22
)
How to find duplicate and sum another index. Which function do you use to
make this work.