Case Statement With Group By I think it is my group by in this syntax that is skewing my desired result set.  I ONLY want to see the data I am requesting, however my query returns all the data like this:

salesman    Q1 2015 Q1 2016
Blue    NULL    NULL 
Blue    NULL    NULL
Blue    200     NULL
Blue    300     NULL
Blue    NULL    400
Blue    NULL    600


What I (thought) my syntax would return would ONLY be the below

salesman    [Q1 2015]   [Q1 2016]
Blue          500          1000


This is my DDL (well garbage data, but gets point across)

Create Table Barnacles
(
  warrantypurchasedate date
  ,salesman varchar(500)
  ,itemprice float
)
Insert Into Barnacles (warrantypurchasedate, salesman, itemprice) Values
('01/01/2014', 'Blue', 100)
,('02/01/2014', 'Blue', 300)
,('01/01/2015', 'Blue', 200)
,('02/01/2015', 'Blue', 300)
,('01/01/2016', 'Blue', 400)
,('02/01/2016', 'Blue', 600)


This is the query syntax I attempted:

Select
salesman
,case when DATEPART(Year, warrantypurchasedate) = '2015' AND DATEPART(Quarter, warrantypurchasedate) = '1' then SUM(itemprice) else NULL end As [Q1 2015]
,case when DATEPART(Year, warrantypurchasedate) = '2016' AND DATEPART(Quarter, warrantypurchasedate) = '1' then SUM(itemprice) else NULL end As [Q1 2016]
FROM Barnacles
GROUP BY salesman, warrantypurchasedate


What should I alter in my query so that I only see the SUM() for Q1 15 and the SUM() for Q1 16 not a row returned for each entry in the table?
Untested, but I believe your query should look like:

SELECT salesman
      ,sum(case when DATEPART(Year, warrantypurchasedate) = '2015'
                 and DATEPART(Quarter, warrantypurchasedate) = '1'
                then itemprice 
           end) As [Q1 2015]
      ,sum(case when DATEPART(Year, warrantypurchasedate) = '2016'
                 and DATEPART(Quarter, warrantypurchasedate) = '1'
                then itemprice 
           end) As [Q1 2016]
FROM Barnacles
WHERE DATEPART(Year, warrantypurchasedate) in ('2015', '2016')
  AND DATEPART(Quarter, warrantypurchasedate) = '1' 
GROUP BY salesman


I moved  sum outside of case, and added a WHERE clause to filter out relevent rows. I also removed date from the GROUP BY clause, otherwise you will get 1 row per date.