Queries :: Show All Names In First Column And Insert Zero Where No Record Exists

I'm tracking the holiday entitlement of a team of people. I use a query to work out how much unbooked holiday they have to take.

My problem is where I'm scheduling next year my query returns the names of those who have booked a holiday and their remaining entitelement. That's as it should be. However if someone hasn't yet booked any holidays then it simply doesn't display their record. I would like it to treat that record as zero and show the remaining entitlement as a full years entitlement.

Here's the SQL
SELECT Employees.Trainer_Name, Sum([2015 Holiday].[2015 Days]) AS [SumOf2015 Days], Employees.Holiday_Days, [Employees]![Holiday_Days]-[SumOf2015 Days] AS 2015
FROM [2015 Holiday] INNER JOIN Employees ON [2015 Holiday].Trainer_Name = Employees.Trainer_Name
GROUP BY Employees.Trainer_Name, Employees.Holiday_Days;

The problem here is that the Sum of 2015 holiday is Null

Do I somehow need to create 0 hours records?