DECLARE @OldESlip as varchar(50),@RandomNumber as int
declare @CourseCode varchar(50)
set @CourseCode ='0001'
SELECT @RandomNumber=cast (CAST(RAND() * 1000000 AS INT) as varchar)
SET @OldESlip ='4'+@CourseCode+cast (@RandomNumber as varchar)
select @OldEslip
I guess the problem you are facing is regarding the Concatenation of string make sure that @CourseCode is a varchar field and ofcourse check that the value coming in @CourseCode is in correct Format
To ensure it Please use Select @CourseCode immediately after begin statement.
I guess it will help