Let's you inherit a table with a column that can contain blanks, empty strings or NULL values. I am saying inherit because surely you would have a constraint on the column that wouldn't allow those values to begin with right? For all the values that are '',' ' or NULL you want to display 'N/A'.
What is the best way to do this? You can Use CASE and test for the values or you can use COALESCE with NULLIF which is much shorter. A lot of people don't know that you can stack these functions so that it makes your life so much easier.
Let's get started
CREATE TABLE Blah (SomeCol VARCHAR(33))
INSERT Blah VALUES(NULL)
INSERT Blah VALUES('')
INSERT Blah VALUES(' ')
INSERT Blah VALUES('A')
INSERT Blah VALUES('B B')
--Using COALESCE and NULLIF
SELECT COALESCE(NULLIF(RTRIM(SomeCol),' '),'N/A')
SELECT CASE WHEN RTRIM(SomeCol) = '' THEN 'N/A'
WHEN RTRIM(SomeCol) IS NULL THEN 'N/A'
ELSE SomeCol END SomeCol
Output for both queries