Excluding Part Of Select Statement If No Data Is Returned In Results

I have a query that returns results based on information in several tables.  The problem I am having is that is there are no records in the one table it doesn't return any information at all.  This table may not have any information initially for the employees so I need to show results whether or not there is anything in this one table.

Here is my select statement:

  SELECT employee.emp_id, DATEDIFF(mm, employee.emp_begin_accrual, GETDATE()) * employee.emp_accrual_rate -
(SELECT SUM(request_duration) AS daystaken
FROM request) AS daysleft, employee.emp_lname + ', ' + employee.emp_fname + ' ' + employee.emp_minitial + '.' AS emp_name,
department.department_name, location.location_name
FROM employee INNER JOIN
request AS request_1 ON employee.emp_id = request_1.emp_id INNER JOIN
department ON employee.emp_department = department.department_id INNER JOIN
location ON department.department_location = location.location_id
GROUP BY employee.emp_id, employee.emp_begin_accrual, employee.emp_accrual_rate, employee.emp_fname, employee.emp_minitial,
employee.emp_lname, department.department_name, location.location_name
ORDER BY location.location_name, department.department_name, employee.emp_lname

 

The section below is the part that may or may not contain information:

  SELECT (SELECT SUM(request_duration) AS daystaken
FROM request) AS daysleft


 

So I need it to return results whether this sub query has results or not.  Any help would be greatly appreciated!!!

TIA