it's just a hit to the db.

Graphql works the same way if i'm not mistaken.

and if its the case that you don't want the comments at all, then in the conditionals write your sql statements

if you want comments

select * from resource where id=some resource id

if you don't

select without comments from resource where id=some resource id

there's no need to get into specifics, the point is graphql is not bringing anything novel. everything it claims to do can be implemented in RESt if you're willing to implement it.