Aggregate functions in GraphQLList object

Addition of aggregate functions in GraphQLList Object such as in SQL:

Example: In order to implement something like:

SELECT post_id, likes, count(likes) FROM posts;

where likes stores the user_ids of users who liked a certain post

as

query AllPosts {
  posts {
    post_id
    likes
    count(likes)
  }
}

and for GraphQLList<GraphQLInt> type data, provide a sum(values) function and so on...