Update SQL stored procedure

create-or-update.sql

-- if the stored procedure does not exist then create a placeholder
if not exists (
  select * from sys.objects where object_id = OBJECT_ID(N' p_MyProc')
  and type = N'P'
) then
  create procedure p_MyProc as RAISERROR ('MyProc not defined', 16, 1);
  grant execute on p_MyProc to SomeRole
end

-- update stored proc
alter procedure p_MyProc as begin
  -- awesome code here
end

drop-and-create.sql

-- Delete the stored procedure if it already exists
if exists (
  select * from sys.objects where object_id = OBJECT_ID(N'p_MyProc')
  and type = N'P'
) then
  drop procedure p_MyProc
end

-- Now create it again
create procedure p_MyProc as begin
  -- awesome code here
end

-- And set permissions
grant execute on p_MyProc to SomeRole