> SELECT * FROM users
+----+---------------------------+
| id | email                     |
+----+---------------------------+
|  5 | abcdefghijklmno@gmail.com |
+----+---------------------------+

> SELECT * FROM movies
+----+---------+---------+--------------+
| id |  title  | user_id | total_watches|
+----+---------+---------+--------------+
|  1 |  X-men  |    1    |     1        |
|  2 |  Blade  |    1    |     1        |
|  3 | Goonies |    1    |     1        |
+----+---------+---------+--------------+

> SELECT * FROM sessions
+----+---------+---------+------------+
| id | user_id | show_id | total_time |
+----+---------+---------+------------+
|  1 |       1 |       1 |          5 |
|  2 |       1 |       1 |         30 |
|  3 |       1 |       1 |          5 |
+----+---------+---------+------------+

+----+---------------------------+---------------+----------------+
| id | email                     |  total_time   |  total_watches |
+----+---------------------------+---------------+----------------+
|  5 | abcdefghijklmno@gmail.com |       40      |        3       |
+----+---------------------------+---------------+----------------+

SELECT users.id, users.email, SUM(movies.total_watches) AS total_watches, SUM(sessions.total_time) AS total_time
FROM users
JOIN movies ON users.id = movies.user_id
JOIN sessions ON users.id = sessions.user_id
GROUP BY user.id

+------------------+---------------+---------------+
| email            | total_watches |   total_time  |
+------------------+---------------+---------------+
| abcdef@gmail.com |       9       |        120    |
+------------------+---------------+---------------+