 
  
  jq '.comments[] | {comment:{url_slug:.post.url_slug, post_id:.post.id}}'{
  "comment": {
    "url_slug": "post-solar-system",
    "post_id": 555555
  }{
  "comment": {
    "url_slug": "post-solar-system",
    "post_id": 555555
    "full_url": "https://экзампл.ком/post-solar-system-555555/"
  } 
             
            