Collect nested objects in new array

The CMS Questions
1

I am querying a database with $votes = Db::select($table, ['votes']);. The ‘votes’ column is of the JSON type. This gives me a Kirby collection. When getting the values of this collection, I receive this array:

Array
(
    [0] => Kirby\Toolkit\Obj Object
        (
            [votes] => [{"rate": "4", "video": "2"}, {"rate": "2", "video": "6"}, {"rate": "4", "video": "8"}, {"rate": "4", "video": "9"}]
        )

    [1] => Kirby\Toolkit\Obj Object
        (
            [votes] => [{"rate": "4", "video": "8"}]
        )

    [2] => Kirby\Toolkit\Obj Object
        (
            [votes] => [{"rate": "4", "video": "7"}, {"rate": "3", "video": "8"}, {"rate": "3", "video": "9"}]
        )
// ect
)

Now, I want to collect every vote object {"rate": x, "video": n} in a new array, in order to perform some operations on the whole data set. If it helps, I want to count all votes, find the average rating for each video and more. This whole procedure should probably be done in SQL, but I don’t know the language.