Left Join Is Returning One value for entire column - sql

Question

I am doing a left join on another table in the subquery and the commission column I want to return from the left join is only bringing one value for the entire commission column which is wrong (see first query result below). Now if I do the left join outside of table A (query 2) then I get the desired results (see second result set). The question is why isn't the left join working within table A in the first query.
I have tried left joining outside of subquery/table A (query 2) and it it works fine but I want to learn why isn't the left join working within the table A.
The query (query 1) is below which is giving the duplicate values in the commission column
Position_A1 table
Sector Short_Side
------------------------
Engineering -2
Financial -5
Industry -10
Corporate -36
Energy -52
Financial -26
Order table
Sector Commission
------------------------
Engineering 10
Financial 100
Industry 36
Corporate 91
Energy 10
Financial 25
Query 1
SELECT *
FROM
(SELECT POS.SECTOR,
SUM(ABS(POS.SHORT_SIDE)) AS Short_Expo,
COM.COMMISSION
FROM Position_A1 POS
LEFT JOIN (SELECT SECTOR, sum(COMMISSION) AS COMMISSION
FROM ORDER
WHERE TRADE_DATE = TO_DATE('2019-11-01','YYYY-MM-DD')
GROUP BY SECTOR
)COM
ON POS.SECTOR = COM.SECTOR
WHERE TRADE_DATE = TO_DATE('2019-11-01','YYYY-MM-DD')
GROUP BY SECTOR ) A
However, if I try the below, I get the correct results in the commission column.
Query 2
SELECT A.*, COM.COMMISSION
FROM
(SELECT POS.SECTOR,
SUM(ABS(POS.SHORT_SIDE)) AS Short_Expo
FROM Position_A1 POS
WHERE TRADE_DATE = TO_DATE('2019-11-01','YYYY-MM-DD')
GROUP BY SECTOR ) A
LEFT JOIN (SELECT SECTOR, sum(COMMISSION) AS COMMISSION
FROM ORDER
WHERE TRADE_DATE = TO_DATE('2019-11-01','YYYY-MM-DD')
GROUP BY SECTOR
)COM
ON POS.SECTOR = COM.SECTOR
As per the first query the result I get is:
Sector Short_Expo Commission
Energy 256 125
Industry 236 125
Financial 125 125
As per the second query the result I get (which is correct) is:
Sector Short_Expo Commission
Energy 256 128
Industry 236 325
Financial 125 186
The question is why isn't query one giving the ideal result whereas query 2. What am I doing wrong in the first query that is resulting in duplicate commission?
Using the first it seems that the commission for only one sector (Financial) is being returned for all sectors.

Answer 1

In the first query, the WHERE clause in the outer query (WHERE TRADE_DATE = TO_DATE('2019-11-01', 'YYYY-MM-DD')) is turning the LEFT JOIN into an INNER JOIN because the non-matching values are NULL and they don't match.
The normal solution is to include filtering on subsequent tables in the ON clause.