Question

I have a SQL query running on SQL Server 2012 that needs to compare a bit value and return a string if that value is 1 and an empty string if it is zero.

Originally I had it as a CASE statement like this:

CASE WHEN myBit = 0 THEN 
 -- do other comparisons etc to build up the return string.
 +'myString' 
ELSE 
-- do other comparisons etc to build up the return string.
'' END

The problem is that all of the code in ‘do other’ section is the same. All I want to do is append a string to the returned value if the bit is zero and nothing if it is 1.

So I refactored it to only have the common code once and then append to the string at the end like this:

-- do other comparisons etc to build up the return string. +
ISNULL(NULLIF(Cast(ISNULL(CAST(NULLIF(myBit, 0) AS NVARCHAR), 'myString') AS varchar),'0'),'')

However the above seems very messy not least because of the CAST statements required.

I’m looking for a clean and neat way of doing this but have run out of ideas – anyone have a better way of achieving this? Thanks.

Answer 1

You can also use IIF and CONCAT as you are on SQL Server 2012.

SELECT CONCAT('Start',
              IIF(@mybit=0,'myString',''),
              'End')

IIF is a bit more concise than CASE. CONCAT might be beneficial in that it casts non string types to strings automatically and concatenating NULL is treated the same as concatenating an empty string.