if not exists (select * from dbo.sysobjects where id = object_id(N'[dbo].[test1]'))
begin
   select 1
   create table test1(id int)
end 
go
if not exists (select * from dbo.sysobjects where id = object_id(N'[dbo].[test]'))
begin
   create proc test(@p_id int )
   as
   begin
      select 3
   end 
end 
go

if  exists (select * from dbo.sysobjects where id = object_id(N'[dbo].[test]'))
  drop proc test
go
create proc test(@p_id int )
as
begin
  select 3
end   
go