How do I incorporate a Double Moving Average in straight SQL in a single query? - sql

Question

EDIT: I need to do this in ACCESS.
I am an SQL virgin and would greatly appreciate any magical assistance!
For a simple 12 month forecast, I am utilizing a 12 month Double Moving Average.
I have managed to pull the Single Moving Average through Query 1 (below).
Based on the table created by Query 1, I have written another query (Query 2) to get the Double Moving Average.
As such, my current process requires two queries. My efforts so far to combine these two steps into a single query have not been successful.
My Question: Is there any way to calculate Double Moving Average in a single query?
QUERY 1 - For Single Moving Average:
SELECT A.*, IIf([A].[VOL]>0,
(SELECT AVG(B.[VOL])
FROM [Turnover] as B
WHERE (B.Code = A.Code) AND (B.YM Between A.YM - 1 AND A.YM - ([12] * 31))),
(SELECT AVG(B.[VOL])
FROM [Turnover] as B
WHERE (B.Code = A.Code) AND (B.YM Between Now() - 31 AND A.YM - ([12] * 31)))) AS [Mvg Avg 1],
INTO [Model 12m]
FROM [Turnover] AS A;
QUERY 2 - Double Moving Average (currently this refers to QUERY 1):
SELECT A.*, IIf([A].[Mvg Avg 1]>0,(SELECT AVG(B.[Mvg Avg 1])
FROM [Model 12m] as B
WHERE (B.Code = A.Code) AND (B.YM Between A.YM - 1 AND A.YM - ([12] * 31))),(SELECT AVG(B.[Mvg Avg 1])
FROM [Model 12m] as B
WHERE (B.Code = A.Code) AND (B.YM Between Now() - 31 AND A.YM - ([12] * 31)))) AS [2 Mvg Avg],
INTO [Model 12m - 2MA]
FROM [Model 12m] AS A;

Answer 1

My Question: Is there any way to calculate Double Moving Average in a
single query?
Since you're using Microsoft Access, there should be no need to do that. Save the first query as a new query. (For people who don't use MS Access, saving the SQL statement as a new query is equivalent to the SQL statement CREATE VIEW ....) Then use the second query as-is, or save it as another new query.
MS Access is really good at optimizing queries built on queries (views built on views).