Oracle monthly totals and grand total column and row - sql

Question

I'm trying to generate a report using Oracle which looks like this:
I got the following tables:
REGION (IDRegion, Region_Name)
SALES (IDSale, Sale_Date, Amount, IDSaleRegion)
Both tables are populated.
I cannot figure out how can I create that report by extracting each sum for the first 3 months and calculate the totals.
I've only made this script but it's not so useful:
SELECT Region_Name as Region,
COALESCE(NULL, NULL) AS "January",
COALESCE(NULL, NULL)AS"February",
COALESCE(NULL, NULL)AS"March",
COALESCE(NULL, NULL)AS"GrandTotal"
FROM REGION r INNER JOIN SALES s ON r.IDRegion=s.IDSaleRegion
GROUP BY Region_Name;
EDIT: Problem solved except the TOTAL (below Region) which calculates the totals from each Month. Any ideas how to add this row?

Answer 1

You can use Conditional Aggregation
select case grouping(Region_Name) when 1 then 'TOTAL' else Region_Name as "Region",
sum(case when extract(month from Sale_Date) = 1 then Amount else 0 end) AS "January",
sum(case when extract(month from Sale_Date) = 2 then Amount else 0 end) AS "February",
sum(case when extract(month from Sale_Date) = 3 then Amount else 0 end) AS "March",
sum(Amount) AS"GrandTotal"
From yourtable
Where extract(month from Sale_Date) <= 3
Group by Rollup (Region_Name);

Answer 2

try something like this:
SELECT Region_Name as Region,
sum(decode(extract(month from Sale_Date), 1, amount)) AS "January",
sum(decode(extract(month from Sale_Date), 2, amount)) AS"February",
sum(decode(extract(month from Sale_Date), 3, amount)) AS"March",
sum(case when extract(month from Sale_Date)<4 then amount end) AS"GrandTotal"
FROM REGION r INNER JOIN SALES s ON r.IDRegion=s.IDSaleRegion
GROUP BY Region_Name;