Question

While reading SQL Server documentation I came across the following statement:

EXEC sp_addlinkedserver   
   @server=N'S1_instance1', 
   @srvproduct=N'',
   @provider=N'SQLNCLI', 
   @datasrc=N'S1\instance1';

What is the “N” before the string arguments? It seems to be optional as, without them, the statement works well.

Answer 1

From here

The “N” prefix stands for National Language in the SQL-92 standard,
and must be uppercase. If you do not prefix a Unicode string constant
with N, SQL Server will convert it to the non-Unicode code page of the
current database before it uses the string.

Some more information from stack exchange is here