Even if you have a column in a table that is specified as nvarchar, you still need to tip off SQL Server that you are handing it a string that contains Unicode when you’re setting values in the column. Witnesseth:
1> create table interjunk(id int not null, inter nvarchar(255))
2> go
1> insert into interjunk(id, inter) values (1, 'Unicode string ψ')
2> insert into interjunk(id, inter) values (2, N'Unicode string ψ')
3> go
(1 row affected)
(1 row affected)
1> select * from interjunk
2> go -m vert
id: 1
inter: Unicode string ?
id: 2
inter: Unicode string ψ
(2 rows affected)