Average, Total and Transpose - sql-server

Question

I have this query below:
SELECT distinct COUNT(Status) AS [Transactions], sender AS [Supplier],
left(DATENAME(mm, Date_Reported), 3) AS Month, DATENAME(yyyy, Date_Reported) AS Year
FROM TX
and Date_Reported >= DATEADD(MONTH, -13, CAST(GETDATE() AS DATE))
GROUP BY DATENAME(mm, Date_Reported), DATENAME(yyyy, Date_Reported), sender
ORDER BY sender, Year, Month DESC;
It gives me a table like below:
TX | Supplier | Month | Year
Now the above can have X rows with the same supplier and a value associated with it like below:
**TX | Supplier | Month | Year**
1 | A | Oct | 2017
5 | A | Jan | 2017
3 | A | Mar | 2018
2 | A | Sep | 2017
This is the case for all of the suppliers, so instead of a long winded table with many rows I want distinct suppliers and their values in a concise table as below:
Supplier | May 17 | Jun 17 | Jul 17 ... | May 18 |
I would also like to add two extra columns: the average of the last 13 months (ie May 17 - May 18) and also the total of the last 13 months, so the final table should look like this:
Supplier | May 17 | Jun 17 | Jul 17 ... | May 18 | Average | Total
I appreciate I am asking a lot, but I hope someone can help me with ONE SINGLE query that can do ALL of the above.
I thank you in advance :)

Answer 1

You would have to do something like this:
SELECT sender AS [Supplier],
SUM(CASE WHEN MONTH(Date_Reported) = 5 AND YEAR(Date_Reported) = 2017 THEN 1 ELSE 0 END) AS [May 17],
SUM(CASE WHEN MONTH(Date_Reported) = 6 AND YEAR(Date_Reported) = 2017 THEN 1 ELSE 0 END) AS [Jun 17]
GROUP BY sender
ORDER BY sender