SET UPDATE CASE WHEN HAVING GROUP BY all in one

Question

I'm a little stuck with the code below that doesn't work. 
Basically in my table i return 3 rows per Name and they should all have the same location too, e.g. 3 Davids and 3 USA.  But sometimes I might have 3 Davids and 2 USA and 1 EU - so in this case I need to update a new column called SplitValue
and enter something like 1 or 0 depending on whether the name has 3 locations that are the same, just so we can report on it.
WITH cte AS (
SELECT name, location,
CASE WHEN [Location] < 2
THEN 'split'
ELSE 'NO Split'
END AS [SplitValue]
FROM [dbo].[Names]
GROUP BY name, location HAVING COUNT(location) < 2
UPDATE [dbo].[Names]
SET [Split] = cte.[splitvalue]

Answer 1

You're almost there.  Try this.
-- SETTING UP SOME TEST DATA TO MIMIC YOUR SOURCE DATA
DECLARE @Names TABLE (name varchar(30), location varchar(30), split varchar(10))
INSERT @Names (name, location) VALUES
('David', 'USA'), ('David', 'USA'), ('David', 'USA'),
('Bob', 'USA'), ('Bob', 'USA'), ('Bob', 'EU'),
('Jane', 'AUS'), ('Jane', 'USA'), ('Jane', 'EU'),
('Alex', 'EU'), ('Alex', 'EU'), ('Alex', 'EU')
;WITH NamesLocationGroups AS
SELECT name
,location
,CASE WHEN COUNT(*) < 2 THEN 'split'
ELSE 'NO Split'
END as splitvalue
FROM @Names
GROUP BY name
,location
UPDATE A SET A.split = B.splitvalue
FROM @Names A
JOIN NamesLocationGroups B
ON A.name = B.name
AND A.location = B.location
SELECT *
FROM @Names
Results will look like this:
name                           location                      
split
David                          USA                           
NO Split
David                          USA                           
NO Split
David                          USA                           
NO Split
Bob                            USA                           
NO Split
Bob                            USA                           
NO Split
Bob                            EU                            
split
Jane                           AUS                           
split
Jane                           USA                           
split
Jane                           EU                            
split
Alex                           EU                            
NO Split
Alex                           EU                            
NO Split
Alex                           EU                            
NO Split