How to write an optimal SQL query with a calculated field?

Question

SQL

Good afternoon, please help me write an optimal SQL query
, there are three tables:

1. Events
   
2. Members
   
3. Users
   

Accordingly, the user registering for the event becomes a participant. The Participants table implements a many-to-many relationship between Events and Users.
Nozhno, for a given user ID to make a selection of all events and add a calculated field of type boolen - whether this user is a participant in the event.
I want to do it in one request, and as quickly as possible

Answer 1

Questions of query optimization do not make sense without specifying the DBMS used.
or

select ..., exists(select null from participations as p on p.user_id = ? and e.id = p.event_id) from events as e

Answer 2

Nozhno

No. It is enough to define there is a "User ID" in "Participants", a subquery, for example.