Trying to get a count of how many people in a unit from the total number of people

My task is to display the total number of students in the school and the number of students in a filtered class (like class 1, class 2, class 3 and so on..). Here is my stored procedure to do the job:

USE [My_DB]
GO
/****** Object:  StoredProcedure [dbo].[CurrentUnitRoster]    Script Date: 7/7/2017 2:56:58 PM ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO

-- =============================================
-- Author:		<OC>
-- Create date: <Create Date,,>
-- Description:	<Description,,>
-- =============================================
ALTER PROCEDURE [dbo].[CurrentUnitRoster] (
	-- Add the parameters for the stored procedure here
	@UIC INT
	)
AS
BEGIN
--IF (@SearchParameter='All' OR @SearchParameter IS NULL OR @SearchParameter ='' OR @searchValue = 'All')
BEGIN
	-- SET NOCOUNT ON added to prevent extra result sets from
	-- interfering with SELECT statements.
	SET NOCOUNT ON;
	WITH MyTest as
(
  SELECT P.UICID, P.ParentUIC_ID, CAST(P.UICID AS VarChar(Max)) as Level
  FROM RefSwcsUIC P
  WHERE P.UICID = @UIC

  UNION ALL

  SELECT P1.UICID, P1.ParentUIC_ID, CAST(P1.UICID AS VarChar(Max)) + ', ' + M.Level
  FROM RefSwcsUIC P1
  INNER JOIN MyTest M
  ON M.UICID = P1.ParentUIC_ID
 )
	--If "ALL" is selected from training unit
		--BEGIN
			SELECT COUNT (DISTINCT sn.studentid)
			FROM studentnames sn
			LEFT OUTER JOIN RefSuffix c
			ON sn.SuffixID = c.SuffixID
			INNER JOIN studentcompcascade scc ON sn.studentid = scc.studentid
			LEFT OUTER JOIN Students s ON sn.studentid = s.studentid
			LEFT OUTER JOIN StudentIDs IDs ON sn.studentid = IDs.studentid
			LEFT OUTER JOIN studentarrdep sa ON sn.studentid = sa.studentid
			LEFT OUTER JOIN studentpipeline sp ON sn.studentid = sp.studentid
			LEFT OUTER JOIN refswcsuic rs ON sa.arrswcsunit = rs.uicid
			LEFT OUTER JOIN studentclearances sc ON sn.studentid = sc.studentid
			LEFT OUTER JOIN RefIDTypes b ON IDs.IDTypeID = b.IDTypeID
			--newly added to display course ID
			LEFT OUTER JOIN RefComp rc ON scc.CompID = rc.CompID
			LEFT OUTER JOIN studentclass scl ON scl.studentid = scc.studentid
			LEFT OUTER JOIN classes cl ON scl.classid = cl.classid AND GETDATE() BETWEEN cl.StartDate AND cl.EndDate
			LEFT OUTER  JOIN RefCourseCode cc on cl.CourseCodeID = cc.CourseCodeID
			LEFT OUTER  JOIN courses c2 on c2.CourseCodeID = cc.CourseCodeID	 AND (cl.StartDate BETWEEN c2.EffDate AND ISNULL(c2.ObsDate, '1/1/9999'))
			LEFT OUTER JOIN RefRank ON scc.RankID = RefRank.NatSvcRankID
	LEFT OUTER JOIN NavyRatingsView f ON scc.PMOSID = f.MOS_ID AND scc.RankID = f.NatSvcRankID
	LEFT OUTER JOIN RefPipelines g on scc.PipelineID = g.PipelineID
			LEFT OUTER JOIN RefDutyStatus ON sa.ArrDutyStatus = RefDutyStatus.DutyStatusID
			LEFT OUTER JOIN RefTrainingStatus ON sp.TrainingStatusID = RefTrainingStatus.TrainingStatusID
			LEFT OUTER JOIN RefTrainingMOS ON scc.TrainingMOSID = RefTrainingMOS.TrainingMOSID
			LEFT OUTER JOIN RefLanguage ON sp.TrainingLanguageID = RefLanguage.LanguageID
			LEFT OUTER JOIN RefClearanceTypes ON sc.ClearanceTypeID = RefClearanceTypes.ClearanceTypeID
	LEFT OUTER JOIN RefMOS e ON scc.PMOSID = e.MOS_ID

			WHERE (rs.uicid IN (SELECT UICID FROM MyTest))
			AND sn.ObsDate IS NULL
			AND sp.ObsDate IS NULL
			AND IDs.ObsDate IS NULL
			AND scc.ObsDate IS NULL
			AND sa.ObsDate IS NULL
	END
END

When I run the program I get the total number of students:

protected void sdsTACStudents_Selected(object sender, SqlDataSourceStatusEventArgs e)
        {
            if (txtSearchByName.Text == "")
            {
                int rowCount = e.AffectedRows;
                txtRecordCount.Text = rowCount.ToString();
            }
            else if ((ddlSearchBy.Text == "LName") || (ddlSearchBy.Text == "FName") || (ddlSearchBy.Text == "SSN"))
            {

                using (SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings["STARS_DB_ConnectionString"].ConnectionString))
                {
                    conn.Open();
                    SqlCommand cmd = new SqlCommand("CurrentUnitTACRoster", conn);
                    cmd.CommandType = CommandType.StoredProcedure;
                    cmd.Parameters.Add("@UIC", SqlDbType.Int);
                    cmd.Parameters["@UIC"].Value = Session["UIC"].ToString();
                    try
                    {
                        string Total = cmd.ExecuteScalar().ToString();  // Total number of students
                        int rowCount = e.AffectedRows;
                        lblUnitRecordCount.Text = rowCount.ToString(); //  Gives me the number of student on the page, I need the number in the class.

                    }
                    catch
                    {

                    }
                    conn.Close();
                }
            }
        }

The question is how do I get the count of students in a class (I use a filter to display the class group)?