T-SQL - Determine number of specific days between 2 dates based on sales - datetime

Question

The Problem: Given a day of the week (1, 2, 3, 4, 5, 6, 7), a starting date and an ending date, compute the number of times the given day of the week appears between the starting and ending dates not inclusive of a date for which there were no sales.
Context:
Table "Ticket" has the following structure and sample content:
i_ticket_id c_items_total dt_create_time dt_close_time
----------------------------------------------------------------------------
1 8.50 '10/1/2012 10:23:00' '10/1/2012 11:05:05'
2 10.50 '10/1/2012 11:00:00' '10/1/2012 11:45:05'
3 8.50 '10/2/2012 08:00:00' '10/2/2012 09:25:05'
4 8.50 '10/4/2012 08:00:00' '10/4/2012 09:25:05'
5 7.50 '10/5/2012 13:22:23' '10/5/2012 14:33:27'
.
.
233 6.75 '10/31/2012 23:20:00' '10/31/2012 23:55:39'
Details
There may or may not be any tickets for one or more days during a month. (i.e. the place was closed that/those day/s)
Days in which the business is closed are not regular. There is no predictable pattern.
Based on Get number of weekdays (Sundays, Mondays, Tuesdays) between two dates SQL,
I have derived a query which returns the number of times a given day of the week occurs between the start date and the end date:
DECLARE #dtStart DATETIME = '10/1/2013 04:00:00'
DECLARE #dtEnd DATETIME = '11/1/2013 03:59:00'
DECLARE #day_number INTEGER = 1
DECLARE #numdays INTEGER
SET #numdays = (SELECT 1 + DATEDIFF(wk, #dtStart, #dtEnd)-
CASE WHEN DATEPART(weekday, #dtStart) #day_number THEN 1 ELSE 0 END -
CASE WHEN DATEPART(weekday, #dtEnd) <= #day_number THEN 1 ELSE 0 END)
Now I just need to filter this so that any zero-dollar days are not included in the count. Any help you can provide to add this filter based on the contents of the tickets table is greatly appreciated!

Answer 1

If I understand correctly, you can use a calendar table to count the number of days where the day of week is n and between the start and end and is a date that has ticket sales, which I guess is when the date exists in tickets and has the sum(c_items_total) > 0
WITH cal AS
(
SELECT cast('2012-01-01' AS DATE) dt, datepart(weekday, '2012-01-01') dow
UNION ALL
SELECT dateadd(day, 1, dt), datepart(weekday, dateadd(day, 1, dt))
FROM cal
WHERE dt < getdate()
)
SELECT COUNT(1)
FROM cal
WHERE dow = 5
AND dt BETWEEN '2012-04-01' AND '2012-12-31'
AND EXISTS (
SELECT 1
FROM tickets
WHERE cast(dt_create_time AS DATE) = dt
GROUP BY cast(dt_create_time AS DATE)
HAVING sum(c_items_total) > 0
)
OPTION (MAXRECURSION 0)
SQLFiddle