T-SQL (SS2K8) :: How To Add Counts To A Query

How to get task counts in a sales report.

The data is located in three tables: Projects, ProjectTasks, Sales.

I need to group the data by month and project. It needs to include sales per month as well as the number of each project task completed that month.

Projects:
ProjectIDName
1Project1

ProjectTasks:
ProTaskIDProjectIDTaskCodeBeginDateEndDate
11 Task11/1/20141/15/2014
21Task21/15/20141/20/2014
31Task3 1/21/20141/29/2014

Sales:
SalesIDProjectIDClosingAmount
11 1/31/2014$5000

Query Output:
ClosingDateProject TotalSalesTask1sTask2sTask3s
1/2014Project1$500011 1

My query so far is:

SELECT right('0' + cast(month(s.closing) as varchar(2)), 2) + '/' + cast(year(s.closing) as varchar(4)) as ClosingDate,
p.name as Project, SUM(s.amount) as TotalSales
FROM Sales s
JOIN Project p ON p.projectID = s.projectID
WHEREs.closing >= DATEADD(mm, -12, GETDATE())
GROUP BY right('0' + cast(month(s.closing) as varchar(2)), 2) + '/' + cast(year(s.closing) as varchar(4)), p.name

This will give me the grouping by month/year and project.