SET @FirstNameVariable = N'Anne'
USE Northwind
GO
-- Declare two variables.
DECLARE @FirstNameVariable NVARCHAR(20),
@RegionVariable NVARCHAR(30)
-- Set their values.
SET @FirstNameVariable = N'Anne'
SET @RegionVariable = N'WA'
-- Use them in the WHERE clause of a SELECT statement.
SELECT LastName, FirstName, Title,Region
FROM Employees
WHERE FirstName = @FirstNameVariable
OR Region = @RegionVariable
GO
这句SET @FirstNameVariable = N'Anne'中的N是什么意思?