Only use first of multiple matches SQL - mysql

Question

I need to find the sum of credits from click_stats where source = 'reward' for all users who have claimed at least one of the 3 promo codes AND have the total clicks displayed.
Tables:
+---------------------------------------------+
| click_stats |
+----+---------+--------+--------+------------+
| ID | Credits | Userid | Source | Clicked |
+----+---------+--------+--------+------------+
| 1 | 10 | jon | reward | 1602216005 |
| 2 | 5 | bob | reward | 1602216504 |
| 3 | 5 | jon | reward | 1602216137 |
| 4 | 5 | bob | reward | 1602216138 |
| 5 | 10 | jon | reward | 1602216139 |
| 6 | 5 | jon | reward | 1602216140 |
| 7 | 10 | bob | reward | 1602216150 |
| 8 | 10 | jon | reward | 1602216150 |
| 9 | 10 | sue | reward | 1602216150 |
| 10 | 10 | sue | prize | 1602216150 |
+----+---------+--------+--------+------------+
+-----------------------+
| promo_used |
+----+--------+---------+
| id | userid | promoid |
+----+--------+---------+
| 1 | bob | 1 |
+----+--------+---------+
| 2 | bob | 2 |
+----+--------+---------+
| 3 | bob | 3 |
+----+--------+---------+
| 4 | jon | 1 |
+----+--------+---------+
| 5 | jon | 2 |
+----+--------+---------+
+------------------------+
| promo_codes |
+----+----------+--------+
| id | code | reward |
+----+----------+--------+
| 1 | forever1 | 20 |
+----+----------+--------+
| 2 | novgfy1 | 250 |
+----+----------+--------+
| 3 | novgfy2 | 500 |
+----+----------+--------+
My Query:
SELECT
click_stats.userid as Name,
sum(credits) as TotalClicks
FROM click_stats
JOIN promo_used
ON click_stats.userid = promo_used.userid
JOIN promo_codes
ON promo_used.promoid = promo_codes.id
WHERE
click_stats.source = 'reward'
and FROM_UNIXTIME(clicked) > '2020-10-08'
and (promo_codes.name like '%forever%'
or promo_codes.name like 'novgfy%')
group by
Name
having
TotalClicks > 10
Results when I run my query (returning the total number of clicks * number of promo codes used):
+--------------------+
| Results |
+------+-------------+
| Name | TotalClicks |
+------+-------------+
| bob | 60 |
+------+-------------+
| jon | 80 |
+------+-------------+
Results I am wanting (the total number of clicks only):
+--------------------+
| Expected Results |
+------+-------------+
| Name | TotalClicks |
+------+-------------+
| bob | 20 |
+------+-------------+
| jon | 40 |
+------+-------------+
The problem (I suspect) is that it is summing the click_stats every time it finds a match for promo_codes.name. I just need to know if one of them has been used and then return the total clicks for that user.

Answer 1

Your understanding of the problem is correct. The join multiplies the rows whenever a user has more than one of the promo codes, and you end up with the same credit summed several times.
I would recommend exists instead:
select cs.userid as name, sum(cs.credits) as totalclicks
from click_stats cs
where cs.source = 'reward' and exists (
select 1
from promo_used pu
inner join promo_codes pc on pc.id = pu.promoid
where
pu.userid = cs.userid
and (pc.name like '%forever%' or pc.name like 'novgfy%')
)
group by cs.userid
having sum(cs.credits) > 10