SQL Server存储过程返回null

Question

我有关于通过某个值创建存储过程的问题，我编写过程但是后面的值包括点，所以他什么也没有返回。

有我的代码：

create procedure GetUserInformationByUsername 
    @username nvarchar(50) 
as
    select 
        ISNULL(u.FirstName, 'Unknown') as [First Name], 
        ISNULL(u.LastName,'Unknown') as [Last Name],
        ISNULL(u.Language,'Unknown') as [speak Language],
        ISNULL(c.CountryName,'Unknown') as [Country Name]  
    from 
        UsersProfile u 
    join 
        Countries c on u.CountryID = c.CountryID
    where 
        u.UserName = @username
go

@username是＆＃34; alex.a＆＃34;我想找到的，

我哪里错了？