Attempting to update table data from another table SQL #SQL - sql

Question

I have two tables, one called whoop_data with fields (id, user_id, date, recovery, sleep, strain)
and another called whoop_user with fields (id, name, average_recovery, average_sleep, average_strain)
I'd like to update the whoop_user average data fields using the whoop_data that is logged. Below are my attempts to do so.
New to SQL - please be kind :)
The code below results in the following table (works as intended):
name
AVG(recovery)
Name2
39.5
Name1
78
Name3
49.5
/*works as intended*/
SELECT name, AVG(recovery) FROM whoop_users JOIN whoop_data
ON whoop_users.id = whoop_data.user_id
GROUP BY name;
Both of the attempts below result in the following table:
Name
average_recovery
Name1
39.5
Name2
39.5
Name3
39.5
I see what is happening, but I don't understand why, how to fix it, or why the statement above DO work as intended and the ones below don't.
/*attempt 1*/
UPDATE whoop_users
SET
average_recovery = (SELECT AVG(recovery)
FROM whoop_users JOIN whoop_data ON
whoop_users.id = whoop_data.user_id
GROUP BY name)
WHERE
EXISTS (
SELECT * FROM whoop_data
WHERE whoop_data.user_id = whoop_users.id );
SELECT * FROM whoop_users;
/*attempt 2*/
WITH a AS
(
SELECT AVG(recovery) as av
FROM whoop_users JOIN whoop_data
ON whoop_users.id = whoop_data.user_id
GROUP BY name
)
UPDATE whoop_users
SET
average_recovery = (SELECT av FROM a);
SELECT * FROM whoop_users;

Answer 1

You must correlate properly the subquery that returns the averages from whoop_data (no joins are needed):
UPDATE whoop_users AS u
SET (average_recovery, average_sleep, average_strain) =
(
SELECT AVG(d.recovery), AVG(d.sleep) avg_sleep, AVG(d.strain)
FROM whoop_data AS d
WHERE d.user_id = u.id
);
If your version of SQLite is 3.33.0+ you could also use the UPDATE...FROM syntax which sometimes performs better:
UPDATE whoop_users AS u
SET average_recovery = d.avg_recovery,
average_sleep = d.avg_sleep,
average_strain = d.avg_strain
FROM (
SELECT user_id,
AVG(recovery) avg_recovery,
AVG(sleep) avg_sleep,
AVG(strain) avg_strain
FROM whoop_data
GROUP BY user_id
) AS d
WHERE u.id = d.user_id;