RethinkDB: join table with array of keys

Question

I have table users like

[
    {
        "id":  "1" ,
        "name": "John",
        "groups":  ["1", "2"]
    }
    {
        "id":  "2" ,
        "name": "Jack",
        "groups":  ["1"] 
    }
]

And table groups like

[
    {
        "id":  "1" ,
        "name": "Admin",
        "description": "Administrator"
    },
    {
        "id":  "2" ,
        "name": "Guest",
        "description": "Dear guest"
    }
]

How can I make ReQL selection query with results like

[
    {
        "id":  "1" ,
        "name": "John",
        "groups":  ["Administrator", "Guest"]
    },
    {
        "id":  "2" ,
        "name": "Jack",
        "groups":  ["Administrator"] 
    }
]

?

and

[
    {
        "id":  "1" ,
        "name": "John",
        "groups":  [
            {
                "id":  "1" ,
                "name": "Admin",
                "description": "Administrator"
            },
            {
                "id":  "2" ,
                "name": "Guest",
                "description": "Dear guest"
            }
        ]
    },
    {
        "id":  "2" ,
        "name": "Jack",
        "groups":  [
            {
                "id":  "2" ,
                "name": "Guest",
                "description": "Dear guest"
            }
        ] 
    }
]

Answer 1

Assuming Javascript API and by using .merge() command:

r.table("users").merge(function(user) {
  return {
    groups: r.table("groups")
      .getAll(r.args(user("groups")))
      .getField("name")
      .coerceTo("array")
  };
})

and

r.table("users").merge(function(user) {
  return {
    groups: r.table("groups")
      .getAll(r.args(user("groups")))
      .coerceTo("array")
  };
})