How to return default value from SQL query

Question

Is there any easy way to return single scalar or default value if query doesn\'t return any row?

At this moment I have something like this code example:

Answer 1

Try ISNULL or COALESCE:

SELECT ISNULL((SELECT TOP 1 Name FROM Users WHERE Id = @UserId), 'John Doe')

The inner select will return nothing if no user exist with this id, the isnull will solve this case.

Answer 2

Try isnull

SELECT IsNULL(Name, 'John Doe')  FROM Users WHERE Id = @UserId

Edit:

drop table users
go
create table users
(id int,name varchar(20))
go
insert into users select 1,'1'
 go
declare @userid int
set @userid = 1
select isnull(username.username, 'John Doe')
from (select @userid as userid) userid
outer apply (SELECT  name as username FROM Users WHERE Id = userid.userid ) username
--outer apply (SELECT  name as username FROM Users WHERE Id = @userid ) username