How to Declare variables in SQL Query using C# .Net

You have to create the StoredProcedure. Write these code which you have mention in the question and call this storedprocedure in C# code.

It should be some what like this:

CREATE PROCEDURE Procedure_Name
	@RNo int,
	@SC  nvarchar(20)
AS
BEGIN	
	SET NOCOUNT ON;
	IF NOT EXISTS(SELECT * FROM Test
	WHERE (@RNo BETWEEN RollNo AND RollNo AND @SC BETWEEN SchoolCode AND SchoolCode)) 
	BEGIN
		INSERT INTO Test VALUES (@RNo,@SC)
	END	
END
GO

Pass values to store procedure from C# code.

Thank You.