How to concatenate columns properly using T-SQL?

Question

I have a address in more than one column in a table.

SELECT FirstName, LastName, StreetAddress, City, Country, PostalCode 
FROM Client

I a

Answer 1

Another solution is to use ISNULL

Select FirstName, LastName
    , ISNULL(StreetAddress+', ','')
      +ISNULL(City+', ','')
      +ISNULL(Country+', ','')
      +ISNULL(PostalCode,'')
FROM Client

If a value is null, then the concatenation result will be null. ISNULL will replace the first expression with the second expression.

http://msdn.microsoft.com/en-us/library/ms184325(v=SQL.90).aspx