How to group by columns in a different table - mysql

Question

I am trying to write a query to return the sum of totalRxCount that is grouped by zipcode.
I have two tables named fact2 and demographic.
My problem is that in the demographic table there are duplicate rows which affects the sum of totalRxCount.
To avoid duplicates I am wanting to only return results where npiNum is distinct.
Right now I have this working but it is grouping by relId (the primary key).
I cannot figure out a way to group by zipcode since this column and totalRxCount are in separate tables.
When I try this I am getting wrong results since it is counting the duplicate rows.
Here is my query. I am wanting to modify this to return results grouped by zipcode instead of relId.
Any input will be greatly appreciated!
SELECT fact2.relID
, SUM(fact2.`totalRxCount`)
FROM fact2
LEFT
JOIN (
SELECT O1.relId, COUNT(DISTINCT O1.npiNum)
FROM demographic As O1
GROUP BY O1.relId
) AS d1
ON d1.`relId` = fact2.relID
LEFT
JOIN (
SELECT O2.relID, Sum(O2.totalRxCount)
FROM fact2 AS O2
GROUP BY O2.relID
) AS p1
ON p1.relID = d1.relId
WHERE (monthEndDate BETWEEN 201911 AND 202010) GROUP BY fact2.relID;
Results:
+-------+---------------------------+
| relID | SUM(fact2.totalRxCount) |
+-------+---------------------------+
| 2465 | 2 |
+-------+---------------------------+
What I've tried
SELECT zipcode, SUM(fact2.`totalRxCount`)
FROM fact2
INNER JOIN demographic ON demographic.relId=fact2.relID
LEFT JOIN (
SELECT O1.`relId`, COUNT(DISTINCT O1.`npiNum`)
FROM demographic As O1
GROUP BY O1.`relId`
) AS d1
ON d1.`relId` = fact2.`relID`
LEFT JOIN (
SELECT O2.`relID`, Sum(O2.`totalRxCount`)
FROM fact2 AS O2
GROUP BY O2.`relID`
) AS p1
ON p1.`relID` = d1.`relId`
WHERE (`monthEndDate` BETWEEN 201911 AND 202010) GROUP BY zipcode;
This is returning the sum multiplied by number of duplicate rows in demographic.
Results:
+---------+---------------------------+
| zipcode | SUM(fact2.`totalRxCount`) |
+---------+---------------------------+
| 66097 | 4 |
+---------+---------------------------+
^ This should be 2
demographic table:
+-------+---------+------------+------------+-----------+------------+------------------------------------+-------+----------+----------+-----------------+------------+-------+--------------+---------+----------+-----------+--------+-------------+--------+--------+----------------+
| relId | zipcode | providerId | writerType | firstName | middleName | lastName | title | specCode | specDesc | address | city | state | amaNoContact | pdrpInd | pdrpDate | deaNum | amaNum | amaCheckDig | npiNum | terrId | callStatusCode |
+-------+---------+------------+------------+-----------+------------+------------------------------------+-------+----------+----------+-----------------+------------+-------+--------------+---------+----------+-----------+--------+-------------+--------+--------+----------------+
| 2465 | 66097 | | A | | | JEFFERSON COUNTY MEMORIAL HOSPITAL | | | | 408 DELAWARE ST | WINCHESTER | KS | | | | AJ4281096 | | | | 11604 | |
| 2465 | 66097 | | A | | | JEFFERSON COUNTY MEMORIAL HOSPITAL | | | | 408 DELAWARE ST | WINCHESTER | KS | | | | AJ4281096 | | | | 11604 | |
+-------+---------+------------+------------+-----------+------------+------------------------------------+-------+----------+----------+-----------------+------------+-------+--------------+---------+----------+-----------+--------+-------------+--------+--------+----------------+
fact2
+-------+----------+-----------------+-----------+-------------------+----------+------------+------------+--------+------------+--------------+------------+---------------+--------------+-----------+--------------+-------------+-----------+--------------+-------------+
| relID | marketId | marketName | productID | productName | dataType | providerId | writerType | planId | pmtTypeInd | monthEndDate | newRxCount | refillRxCount | totalRxCount | newRxQuan | refillRxQuan | totalRxQuan | newRxCost | refillRxCost | totalRxCost |
+-------+----------+-----------------+-----------+-------------------+----------+------------+------------+--------+------------+--------------+------------+---------------+--------------+-----------+--------------+-------------+-----------+--------------+-------------+
| 2465 | 10871 | GALT PP MONTHLY | 1399451 | ZOLPIDEM TARTRATE | 15 | | A | 900145 | C | 202004 | 1 | 0 | 1 | 30 | 0 | 30 | 139 | 0 | 139 |
| 2465 | 10871 | GALT PP MONTHLY | 1399458 | ESZOPICLONE | 15 | | A | 900145 | C | 202006 | 1 | 0 | 1 | 30 | 0 | 30 | 350 | 0 | 350 |
+-------+----------+-----------------+-----------+-------------------+----------+------------+------------+--------+------------+--------------+------------+---------------+--------------+-----------+--------------+-------------+-----------+--------------+-------------+