How to efficiently merge hashes by key

How to efficiently merge hashes by key

I have the following array
[ {"date"=>"July 2013", "view"=>12245},
{"date"=>"July 2013", "click"=>916},
{"date"=>"August 2013", "view"=>34889},
{"date"=>"August 2013", "click"=>2012} ]
And here is the desired output:
[ {"date"=>"July 2013", "view"=>12245, "click"=>916},
{"date"=>"August 2013", "view"=>34889, "click"=>2012} ]
What would be the most efficient implementation?