Error: CREATE/ALTER PROCEDURE must be the first statement in a query batch

I had not come across this error before so was a new one for me. 

declare @cmd varchar(200)
set @cmd = 'sp_rename myproc1, myproc'
exec @cmd
GO

create procedure myproc (input_id int)
as
begin
  if input_id = 0
  begin
    print 'i am in begin block #2'
  end
end

The GO indicates end of batch or acts as a batch separator was missing from the script and as a result the error was generated. Once i added the GO statement, the script executed like a happy little monster....

Hope this helps....