T-SQL CASE Clause: How to specify WHEN NULL

Question

I wrote a T-SQL Statement similar like this (the original one looks different but I want to give an easy example here):

SELECT first_name + 
    CASE last_na         


        

Answer 1

The WHEN part is compared with ==, but you can't really compare with NULL. Try

CASE WHEN last_name is NULL  THEN ... ELSE .. END

instead or COALESCE:

COALESCE(' '+last_name,'')

(' '+last_name is NULL when last_name is NULL, so it should return '' in that case)

Answer 2

Found a solution to this. Just ISNULL the CASE statement:

ISNULL(CASE x WHEN x THEN x ELSE x END, '') AS 'BLAH'

Answer 3

Use the CONCAT function available in SQL Server 2012 onward.

SELECT CONCAT([FirstName], ' , ' , [LastName]) FROM YOURTABLE