请SQLite高手帮忙把SQLite语句转换成SQL Server,该如何处理

请SQLite高手帮忙把SQLite语句转换成SQL Server
SQLite语法如下，谢谢！

SQL code

update category set path =
  case 
    when parent_id=0 then '/'
    else (select path from category where id = new.parent_id) || parent_id || '/'
  end
  where id = new.id;

------解决方案--------------------
update category set path =
case 
when parent_id=0 then '/'
else (select path from category where id = new.parent_id) + parent_id + '/'
end
where id = new.id;
是TRIGGER中？