How to fetch from MongoDB?

Question

JavaScript

Hello! The question arose, rather from an insufficient understanding of how to make a selection from the database.
For example, we have the following collections:
Users: {_id, name, password, email}
Teams: {_id, name, team_leader, team_members: []}
Clients: {_id, name, team_id, profile: [], users_access: []}
Tasks: {_id, task, team_id, user_creator_id, access_users: []}
I don't understand at all how to select clients and tasks for a team member if he has access (users_acces).
In my understanding:

1. Get team id by user id
   
2. We make a selection from clients or tasks by user ID and team ID
   

The only question is how to do it?
Or did I design the base incorrectly?
How do I generally switch from MySQL to MongoDB?
Yes, I understand that it's easier to take MySQL and not worry. But the next project is planned for MeteorJS and only Mongo here.

Answer 1

Sampling works fine in mongo

Clients.find({ users_access: this.userId})
Tasks.find({access_users: this.userId}

)
Despite the fact that access_users is an array of user IDs, { access_users: id } allows you to select those documents where the value is included in the array