MySQL - Getting a position from a "leaderboard" - mysql

Question

I'm trying to construct a query where I would get a leaderboard-like result, then get the position on the leaderboard of a specific player, by their ID, and only if the player isHere = 'true' (stored in another table).
Table here:
userID | isHere |
--------------------
2 | true
--------------------
1 | true
--------------------
3 | false
--------------------
4 | true
Table userdata:
id | data |
------------------------------------
2 | {... "points": 5 ...}
------------------------------------
1 | {... "points": 10 ...}
------------------------------------
3 | {... "points": 2 ...}
------------------------------------
4 | {... "points": 28 ...}
Query:
SET
#row_number = 0;
SELECT
*
FROM
(
SELECT
(#row_number := #row_number +1) AS num,
userdata.id,
userdata.data
FROM
userdata
INNER JOIN
here ON userdata.id = here.userID
WHERE
here.isHere = 'true'
ORDER BY
JSON_EXTRACT(userdata.data,
'$.points') DESC
) AS t
WHERE
t.id = 1
This returns that num is 1... because for some reason it's sorting by userID/id. I double checked by setting WHERE t.id = as 2, and instead of returning 3, it returns 2... Does anyone know what's wrong with my query?
Note: I did try having the column data be just a BIGINT with the point value, but the same issue happened. So that eliminates JSON_EXTRACT() having any issues (I think?)
Note 2: Running the inner query on its own still orders by the ID with the num column, but displays in PHPMyAdmin in the correct order (Screenshot: https://gyazo.com/73177e79f4fedd4ec7e09ea0e70a9d2b)

Answer 1

So here's the query that works:
SET
#row_number = 0;
SELECT
*
FROM
(
SELECT
(#row_number := #row_number +1) AS num,
userdata.id,
userdata.data
FROM
userdata
INNER JOIN
(
SELECT
userdata.id,
userdata.data
FROM
userdata
INNER JOIN
here ON userdata.id = here.userID
WHERE
here.isHere = 'true'
ORDER BY
JSON_EXTRACT(userdata.data,
'$.points') DESC
) AS t ON userdata.id = t.id
) AS t2
WHERE
id = ?
The only reason all of this is needed, is due to the order in which MySQL executes parts of queries. Just like parenthesis are used in math in order of operations, I used a SELECT statement here.