How to combine two tables in a stored procedure to pass the alias name in the datafield in aspgrid view

<pre>
Alter procedure [dbo].[Sampe3](@years int,@months int)
as

;with t1 as (
SELECT DeptID, COUNT(EmpID) AS TotalHeadCount  FROM EmployeeDetails          
WHERE (datepart(yyyy,DOJ) between 2005 and @years) and Status =0
group by DeptID
),
t2 as (
SELECT  DeptID,COUNT(EmpID) AS NewJoinees FROM EmployeeDetails AS EmployeeDetails_7        
WHERE (DATEPART(yyyy, DOJ) = @years) AND (DATEPART(mm, DOJ)  = @months) and datepart(mm,DOJ)>= @months and Status = 0
group by DeptID
),
t3 as (
SELECT   DeptID,COUNT(EmpID) AS Resigned FROM  EmployeeDetails AS EmployeeDetails_7                           
WHERE (DATEPART(yyyy, deactivate) = @years) AND (DATEPART(mm, deactivate)  = @months) and datepart(mm,deactivate)>= @months and Status =1 group by DeptID
)
Select t1.DeptID, CASE WHEN TotalHeadCount IS NULL THEN '0' ELSE TotalHeadCount END AS TotalHeadCount,CASE WHEN NewJoinees IS NULL THEN '0' ELSE NewJoinees END AS NewJoinees,CASE WHEN Resigned IS NULL THEN '0' ELSE Resigned END AS Resigned, '' as ToBeHired, '' as OpenPositions, '' as Status
from t1 full outer join t2 on t1.DeptID = t2.DeptID
full outer join t3 on t1.DeptID = t3.DeptID
union
Select 'ZTotal' as total, '' as TotalHeadCount, '' as NewJoinees, '' as Resigned, '' as ToBeHired, '' as OpenPositions, '' as Status

(Update RecruitmentDetails set Tobehired=@Tobehired, OpenPosition=@OpenPosition, Status=@Status) As Update

<asp:GridView ID="grdvEmployeeLeaveUpdate" runat="server" DataKeyNames="" 
                         class="table table-bordered table-striped table-hover" DataSourceID="SqlDataSourceHeadCount"   
                        OnRowDataBound="grdvEmployeeLeaveUpdate_RowDataBound"  Width="100%"
                        OnRowDeleting="grdvEmployeeLeaveUpdate_RowDeleting"
                        OnRowEditing="grdvEmployeeLeaveUpdate_RowEditing"
                        OnRowUpdating="grdvEmployeeLeaveUpdate_RowUpdating"
                        OnRowCancelingEdit="grdvEmployeeLeaveUpdate_RowCancelingEdit"
                         OnPageIndexChanging="grdvEmployeeLeaveUpdate_PageIndexChanging">
                        
                        <Columns>
                            <asp:BoundField DataField="DeptID"  HeaderText="Cost Center" ReadOnly="true" ControlStyle-Width="50px"  />
                            <asp:BoundField DataField="TotalHeadCount" HeaderText="HeadCount" ReadOnly="true" ControlStyle-Width="50px"   />
                            <asp:BoundField DataField="NewJoinees" HeaderText="Additions" ReadOnly="true" ControlStyle-Width="50px"  />
                            <asp:BoundField DataField="Resigned" HeaderText="Separations" ReadOnly="true" ControlStyle-Width="50px"  />
                            <asp:BoundField DataField="ToBeHired" HeaderText="To Be Hired"  ControlStyle-Width="50px" />
                            <asp:BoundField DataField="OpenPositions" HeaderText="Open Position" ControlStyle-Width="50px" />
                            <asp:BoundField DataField="Status" HeaderText="Status"  ControlStyle-Width="50px" />
                            <asp:CommandField HeaderText="Update" ShowEditButton="True" ControlStyle-Width="50px" />
                            
                        </Columns>
                        <HeaderStyle></HeaderStyle>
                    </asp:GridView>

<asp:SqlDataSource ID="SqlDataSourceHeadCount" runat="server" ConnectionString="<%$ ConnectionStrings:TimeSheetConnectionString2 %>"
                                        SelectCommandType="StoredProcedure" SelectCommand="Sampe3">
                                        <SelectParameters>
                                            <asp:ControlParameter ControlID="ddlMonths" Name="months" Type="Int32" />
                                            <asp:ControlParameter ControlID="ddlyear" Name="years" Type="Int32" />
                                        </SelectParameters>
                                    </asp:SqlDataSource>