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

You could use Case-Expression.

create table #Client(
FirstName varchar(20), 
LastName varchar(50), 
StreetAddress varchar(50), 
City varchar(20), 
Country varchar(20), 
PostalCode varchar(20)
)
insert into #Client(FirstName,LastName,StreetAddress,City,Country,PostalCode)values('Jeff','Bridges','Street1','City1','US','12345')
insert into #Client(FirstName,LastName,StreetAddress,City,Country,PostalCode)values('Steven','Baldwin','Street2','City2','US','12345')
insert into #Client(FirstName,LastName,StreetAddress,City,Country,PostalCode)values('Barack','Obama','Street3',NULL,'US','12345')
insert into #Client(FirstName,LastName,StreetAddress,City,Country,PostalCode)values('Nora','Jones','Street4','City4','US','12345')

SELECT FirstName, LastName,
(CASE WHEN City IS NULL AND StreetAddress IS NULL THEN '' 
      WHEN City IS Null AND StreetAddress IS NOT NULL Then StreetAddress 
      WHEN City IS NOT Null AND StreetAddress IS NOT NULL THEN StreetAddress + ',' + City END
)AS Adress, Country, PostalCode 
FROM #Client

drop table #Client