cumulative sum for each user and sorting - mysql

Question

I'm trying to get the cumulative sum for each user.
related tables(just example):
[user]
id
nickname
A
AA
B
BB
[pointTable] user_id -> [user]id
id
user_id
point
piA
A
10
piB
B
8
[pointHistoryTable] point_id -> [point]id
id
point_id
gain
use
phi1
piA
25
0
phi2
piB
10
0
phi3
piA
0
10
phi4
piB
0
9
phi5
piB
7
0
(For gain-use column, only one of them has a value.)
The result I want:
nickname
current
cGainSum
cUseSum
AA
10
25
10
BB
8
17
9
The query I used(mysql v5.7):
#1
SELECT
user.nickname AS nickname,
pointTable.point AS current,
sub.cGainSum AS cGainSum,
sub.cUseSum AS cUseSum
FROM
(SELECT
point_id, SUM(gain) AS cGainSum, SUM(`use`) AS cUseSum
FROM
pointHistoryTable
GROUP BY point_id) sub
INNER JOIN
pointTable ON pointTable.id = sub.point_id
INNER JOIN
user ON user.id = pointTable.user_id
ORDER BY cGainSum DESC
LIMIT 20 OFFSET 0;
#2
SELECT
user.nickname AS nickname,
pointTable.id AS pointId,
pointTable.point AS current,
(SELECT
IFNULL(SUM(gain), 0)
FROM
pointHistoryTable
WHERE
point_id = pointId AND gain > 0) AS cGainSum,
(SELECT
IFNULL(SUM(`use`), 0)
FROM
pointHistoryTable
WHERE
point_id = pointId AND `use` > 0) AS cUseSum
FROM
pointTable
INNER JOIN
user ON user.id = pointTable.user_id
ORDER BY cGainSum DESC
LIMIT 20 OFFSET 0;
Both work. But sorting takes a long time. (20,000 users)
When sorting with current, #1 takes about 25s and #2 takes about 300ms.
However, when sorting by cumulative sum(cGainSum or cUseSum), #1 takes about 25s again and #2 takes about 50s.
So #1 always causes a slow query, and #2 causes a slow query when sorting by cumulative sum.
Any other suggestions?
++
I'm using this query in node api. The data is sorted by the request query. The request query can be current, cGainSum, or cUseSum.
like this...
SELECT (...) ORDER BY ${query} DESC LIMIT 20 OFFSET 0;
The offset uses the pagination related request query.
(included in the details)

Answer 1

I imagine that without all those sub queries it would run faster with just simple joins and aggregate function if I misunderstood something you are welcome to correct me, this is anyways what I came up with
SELECT user.nickname,pointTable.point,SUM(pointHistoryTable.gain), SUM(pointHistoryTable.use) FROM user
LEFT JOIN pointTable
ON user.id=pointTable.user_id
LEFT JOIN pointHistoryTable
ON pointHistoryTable.point_id=pointTable.id
GROUP BY user.id
ORDER BY ${query} DESC LIMIT 20 OFFSET 0;
EDIT:
Besides improving the query, like not creating to complicated subqueries etc. A very easy way to improve performance is the use of indexes. I would for starters create indexes for all the id's in all the tables. You simple do this by using CREATE INDEX indexname ON tablename (column1,column2, etc) in your case for pointHistory the query would look something like this
CREATE INDEX pointHistoryIndex ON pointHistoryTable ('id','point_id')