syntax error in stored procedure

Question

this is my stored procedure

 

 i need to check the empid null or not

 

after i need to check the empid exists or not in the employee table

 

please help me this  

 

ALTER PROCEDURE [dbo].[SP_Details1]

@empID varchar(50)

AS

BEGIN

Declare @records varchar(max)

IF ISNULL(@EmpId,0)!=0

IF EXISTS (

set @records='empid doesnot exist'

)

BEGIN

select @records= [Num] from [Employee] where [Num]= @empID

select @records as [EmpID]

END

END