Grouping SQL results at 2 sub levels - sql

Question

I am using an Access front end screen and SQL queries at the back end. I am trying to get a result set that is grouped at 2 levels: Region & Month and then a relevant count of total clients active in that period, clients with orders and clients without orders all within the period selected by the user.
Below are the 2 tables in use
Client Table A
ID | Region | StartDate | Name
1 | North | 1 Jan 16 | ABC
2 | North | 1 Mar 16 | DEF
3 | East | 1 Jul 16 | GHE
4 | East | 1 Aug 16 | HIJ
5 | West | 1 Feb 16 | KLM
6 | West | 1 Mar 16 | NOP
7 | South | 1 Apr 16 | QUR
8 | South | 1 Jan 16 | STU
Orders Table B
OrderID | Client ID |Order Date
1 | 1 | 15 Mar 16
2 | 3 | 15 Jul 16
3 | 5 | 15 Jun 16
4 | 8 | 15 Jul 16
5 | 6 | 15 Jul 16
6 | 4 | 15 Jan 16
7 | 2 | 15 Feb 16
8 | 1 | 15 Jul 16
9 | 3 | 05 Aug 16
10 | 3 | 16 Jul 16
11 | 2 | 15 May 16
12 | 4 | 15 May 16
13 | 6 | 15 May 16
14 | 7 | 15 Mar 16
The User picks a start date and end date for the report for Eg 1 May 2016 to 31 Jul 16
I need a query that will evaluate if client start date is within reporting period and produce the following out put:
Result Set
Region | Month |Total Clients|Clients with Orders|Clients w/o Orders
North |May-2016| 2 | 1 | 1
North |Jun-2016| 2 | 0 | 2
North |Jul-2016| 2 | 1 | 1
East |May-2016| 0 | 0 | 0
East |Jun-2016| 0 | 0 | 0
East |Jul-2016| 1 | 1 | 0
West |May-2016| 2 | 1 | 1
West |Jun-2016| 2 | 0 | 2
West |Jul-2016| 2 | 1 | 1
South |May-2016| 2 | 0 | 2
South |Jun-2016| 2 | 0 | 2
South |Jul-2016| 2 | 1 | 1
Ive been stuck on this for 2 weeks now.. Please Help!!!
if it helps this is how far I have gotten
PARAMETERS startDt DateTime, endDt DateTime, loc Text ( 255 );
SELECT DISTINCT a.[Region] AS Region,
Format(b.[Orderdate],"MMM-YY") AS MonthOrder,
(Select Count(CMet.[clientID]) as cnt from
(SELECT distinct b.[orderID], Format(b.[order date],"MMM-YY")
as Contact_Month, a.[clientID], a.[Region]
FROM Client as a
INNER JOIN orders AS b ON a.[client ID] = b.[client id]
WHERE iif(isnull(loc),a.[REgion] like '*',instr (loc,a.[region]))
and (b.[orderdate] between startDt and endDt)
and (a.[Start date] < startDt)
GROUP BY a.[Region], Format(b.[order date],"MMM-YY"),
a.[clientID], a.[Region]
HAVING count(a.[clientID]) >=1) as CMet) AS Clients_Met,
(select count([client id]) from clients where
iif(isnull(loc),[region] like '*',instr (loc,[region])) and
client.[Start date] < startDt AS Total_Client,
(Total_Client-Clients_Met) AS Not_Met,
format(Clients_Met/iif(Total_Client =0,1,Total_Client),'##.##%') AS Met_Percentage
FROM clients AS a
INNER JOIN orders AS b ON a.[client ID]=b.[client id]
WHERE iif(isnull(loc),a.[region] like '*',instr (loc,a.[region]))
and (a.[Start date] < startDt
GROUP BY a.[region], Format(b.[order date],"MMM-YY")
HAVING count(a.[client id]) >=1
ORDER BY a.[region];

Answer 1

I tried the solution below. The idea is to do the grouping in the inner query, then do the summing in the outer one:
SELECT Region, Month, Count(ID) AS Clients, Sum(HasOrder) AS ClientsWithOrders,
[Clients]-[ClientsWithOrders] AS ClientsWithoutOrders
FROM (SELECT Region, CDate(Month([Order Date]) & "/1/" & Year([Order Date])) AS [Month],
ID, Max(IIf([Client ID]=[ID],1,0)) AS HasOrder
FROM Orders, Client
WHERE ((([Order Date])>=#5/1/2016# And
([Order Date])<DateAdd("d",1,#7/31/2016#)))
GROUP BY Region, CDate(Month([Order Date]) & "/1/" & Year([Order Date])), ID)
AS RegionMonthClient
GROUP BY Region, Month
The difficulty is I'm getting different results from you. For example, for East clients (3,4) I see one with an order in May (client 4) and one with an order in July (client 3).
Is this approach useful to you in any way?

Answer 2

You can use the join statement and to check the date use the BETWEEN operation. Here is the link for sample join statement and Between Opration.