sql - Perform JOIN query in google cloud firestore

Question

{  
   "users":{  
      "userid_1":{  
         "following":{  
            "userid_2":{  
               "name":"user2"
            },
            "userid_3":{  
               "name":"user3"
            }
         }
      },
      "posts":{  
         "postid1":{  
            "createdTime":"111",
            "postedBy":"userid_2"
         },
         "postid2":{  
            "createdTime":"112",
            "postedBy":"userid_3"
         },
         "postid3":{  
            "createdTime":"113",
            "postedBy":"userid_2"
         },
         "postid4":{  
            "createdTime":"114",
            "postedBy":"userid_1"
         }
      }
   }
}

I want to retrieve the posts of "userid_1"'s following users sorted by created time by the limit 2 (2 posts per api call).

How to achieve in fire-store query in node?

Its ok to fetch all the following user's post and sorting the post by created time if following users are less than 100 and they have 10 posts.

If a user have 1000 following people and the 1000 people have 100 posts then its not ok to fetch all the following user's post and sorting by the created time.

I hope we can achieve this easily by SQL "JOIN" query

How to achieve this implementation query in fire-store in node?

Answer 1

Waitting for answers