select from table between dates and count duplicates - sql

Question

I have a table named tblOrders
| ID | name | email | amount | date |
+-----+---------+------------+---------+------------+
| 1 | danny | dan#email | $10.00 | 06/01/2015 |
| 2 | bryan | bra#email | $50.00 | 06/01/2015 |
| 3 | jenny | jen#email | $20.00 | 06/02/2015 |
| 4 | gabby | gab#email | $35.00 | 06/02/2015 |
| 5 | lisa | lisa#email | $12.00 | 06/03/2015 |
| 6 | don | don#email | $23.00 | 06/04/2015 |
| 7 | danny | dan#email | $22.00 | 06/04/2015 |
| 8 | bryan | bra#email | $55.00 | 06/05/2015 |
| 9 | danny | dan#email | $69.00 | 06/20/2015 |
| 10 | danny | dan#email | $49.00 | 06/25/2015 |
I want to select from tblOrders between date 06/03/2015 and 06/25/03/2015
and then count the number of repeated customers I have.
Select between date 06/03/2015 and 06/25/03/2015 provides
| ID | name | email | amount | date |
+----+-------+------------+--------+-------------+
| 5 | lisa | lisa#email | $12.00 | 06/03/2015 |
| 6 | don | don#email | $23.00 | 06/04/2015 |
| 7 | danny | dan#email | $22.00 | 06/04/2015 |
| 8 | bryan | bra#email | $55.00 | 06/05/2015 |
| 9 | danny | dan#email | $69.00 | 06/20/2015 |
| 10 | danny | dan#email | $49.00 | 06/25/2015 |
Then checking by email from those records if exist in all tblOrders and count
This should provide count of 2 as there are 2 customers between those dates that ordered before.
How can I achieve that with one SQL query?
I'm using Access database and ASP classic
My current code is
ReturnCustomers = 0
Set rs = Server.CreateObject("ADODB.Recordset")
SQL = ("select ID,Email,OrderDate from tblOrders Where OrderDate between #"&date1&"# and "&date2&";")
rs.Open SQL,Cnn,3,1
Do while Not rs.EOF
Set rsCount = Server.CreateObject("ADODB.Recordset")
SQL = ("select ID from tblOrders Where Email='"&rs("Email")&"' and Not ID="&rs("ID")&";")
rsCount.Open SQL,Cnn,3,1
IF Not rsCount.EOF Then
ReturnCustomers = ReturnCustomers+1
End IF
rsCount.Close
Set rsCount = Nothing
rs.MoveNext
Loop
rs.Close
Set rs = Nothing
response.write ReturnCustomers
How can I do this one in 1 SQL query?

Answer 1

It seems you want repeat customers --- those who made a purchase during the target date range and also made a purchase sometime before the start of that date range.
First create a query to retrieve those unique customers:
SELECT DISTINCT o1.email
FROM
tblOrders AS o1
INNER JOIN tblOrders AS o2
ON o1.email = o2.email
WHERE
(o1.date Between #2015-6-3# And #2015-6-25#)
AND o2.date < #2015-6-3#;
However you actually want only the count of those customers. So you can use the first query as a subquery and derive the count from that:
SELECT Count(sub.email) AS CountOfemail
FROM
(
SELECT DISTINCT o1.email
FROM
tblOrders AS o1
INNER JOIN tblOrders AS o2
ON o1.email = o2.email
WHERE
(o1.date Between #2015-6-3# And #2015-6-25#)
AND o2.date < #2015-6-3#
) AS sub;

Answer 2

you are not looking for duplicates. If you want to find out who ordered between date #06/03/2015# to #06/25/03/2015# and ordered before #06/03/2015# , your query should be like :
select distinct name, email from tblorders o
where date >=#06/03/2015# and date < #06/25/03/2015#
and exists (select * from tblorders p where p.email = o.email
and p.date <#06/03/2015# )
Also please specify your sql system.