Aggregation level issue on Teradata/SQL - sql

Question

I am currently learning SQL, as a beginner so apologies if I ask a beginner question. The database I am working on is on of a brand of shopping centers.
I have written a query to retrieve the difference in revenue per store from november to december, which seems OK to me except if I missed something.
Now I would like to adapt it to retrieve which Sku has the biggest the difference of revenue from november to december.
However the query doesn't work, and my results show no data in almost all columns, let alone the calculation column.
Here is my first query (the subquery is there only to clean the data):
SELECT TOP 5 SalesCleaned.Store AS Store, skuinfo.dept AS Dept,
store_msa.city AS City, store_msa.state as State,
SUM(CASE WHEN MonthNb=11 THEN Amount END) AS AmtNov,
SUM(CASE WHEN MonthNb=12 THEN Amount END) AS AmtDec,
SUM(CASE WHEN MonthNb=11 THEN NbOfDates END) AS DNov,
SUM(CASE WHEN MonthNb=12 THEN NbOfDates END) AS DDec,
AmtNov/DNov AS AvgNov, AmtDec/DDec AS AvgDec, (AvgDec-
AvgNov)/AvgNov*100 AS Change
FROM
Skuinfo, store_msa,
(SELECT trnsact.sku as Sku, trnsact.store AS Store, EXTRACT(MONTH from
saledate) as MonthNb, EXTRACT(Year from saledate) AS Yr, SUM(amt) AS
Amount, COUNT(DISTINCT saledate) AS NbOfDates, Amount/NbOfDates AS
AvgPStore, CASE WHEN (Yr=2005 AND MonthNb=8) THEN 'exclude' ELSE
'include' END AS UseDate
FROM trnsact
WHERE(UseDate='include') AND (stype='P')
GROUP BY MonthNb, Store, Yr, stype, Sku
HAVING(NbOfDates>=20)) AS SalesCleaned
WHERE SalesCleaned.store=store_msa.store AND
skuinfo.sku=SalesCleaned.sku
GROUP BY SalesCleaned.Store, City, State, Dept
ORDER BY Change DESC;
And here is the 2nd query, which returns a result wiht a lot of data mmissing, and which I have no idea how to fix:
SELECT SalesCleaned.sku AS Sku,
SUM(CASE WHEN MonthNb=11 THEN Amount END) AS AmtNov,
SUM(CASE WHEN MonthNb=12 THEN Amount END) AS AmtDec,
(AmtDcb - AmtNov)/ AmtDcb *100 AS Change
FROM
(SELECT trnsact.sku AS Sku, trnsact.store AS Store, EXTRACT(MONTH from
saledate) as MonthNb, EXTRACT(Year from saledate) AS Yr, SUM(amt) AS
Amount, COUNT(DISTINCT saledate) AS NbOfDates, Amount/NbOfDates AS
AvgPStore, CASE WHEN (Yr=2005 AND MonthNb=8) THEN 'exclude' ELSE
'include' END AS UseDate
FROM trnsact
WHERE(UseDate='include') AND (stype='P')
GROUP BY Sku, Store, MonthNb, Store, Yr, stype) AS SalesCleaned
GROUP BY Sku, MonthNb, Amount, NbOfDates
HAVING NbOfDates>=20
ORDER BY Change DESC;
Any feedback welcome