Question

I have the following database design:

Employee Table: Username, Name, DivisionCode
Division Table: SapCode, DivisionShortcut
Courses Table: CourseID, CourseName, GroupID
Groups Table: GroupID, GroupName
Employee_Courses Table: EmployeeID, CourseID

I came up with the following query that shows the divisions, courses and the total number of participants in each division:

SELECT     dbo.Divisions.DivisionShortcut, dbo.courses.CourseName, COUNT(dbo.employee_courses.courseId) AS [Total Number of Participants]
FROM         dbo.courses INNER JOIN
                      dbo.employee_courses ON dbo.courses.CourseID = dbo.employee_courses.courseId INNER JOIN
                      dbo.groups ON dbo.courses.GroupID = dbo.groups.ID RIGHT OUTER JOIN
                      dbo.employee AS employee_1 INNER JOIN
                      dbo.Divisions ON employee_1.DivisionCode = dbo.Divisions.SapCode ON dbo.employee_courses.employeeId = employee_1.Username
WHERE     (dbo.courses.GroupID = 1)
GROUP BY dbo.courses.CourseID, dbo.courses.CourseName, dbo.Divisions.DivisionShortcut

In addition to be shown above, I want to display the total number of employees in each division and the percent completion in each division, too. By the way, the percent completion is equal to (total number of participants in each course / total number of employees in each division)

So how to do that?

Answer 1

You could use a subquery to add the total employee count to the join on Divisions. For example:

SELECT  d.DivisionShortcut
,       c.CourseName
,       d.EmployeeCount as DivisionEmployees
,       count(c.courseId) as CompletedCourses
,       100.0 * count(c.courseId) / d.EmployeeCount as PercentageCompleted
FROM    dbo.courses c
JOIN    dbo.employee_courses ec
ON      c.CourseID = ec.courseId
JOIN    dbo.employee e
ON      ec.employeeId = e.Username
JOIN    (
        select  d2.SapCode
        ,       d2.DivisionShortcut
        ,       count(e2.DivisionCode) as EmployeeCount
        from    dbo.Divisions d2
        JOIN    dbo.employee e2
        ON      d2.SapCode = e2.DivisionCode
        group by
                d2.SapCode
        ,       d2.DivisionShortcut
        ) d
ON      d.SapCode = e.DivisionCode
WHERE   c.GroupID = 1
GROUP BY 
        d.DivisionShortcut
,       d.EmployeeCount
,       c.CourseName