Sql 联合仅选择一行

我有一个带UNION的两个Select子句组合的查询。我只想选择最上面的第一行。我如何使用Union来实现这一点

Select Fault,OccurredOn From ATMStatus Where Ticket=189703 // This Will retrieve single record as the primary key is applied
Union 
Select Fault,OccurredOn From ATMStatusHistory Where Resolved=0 AND Ticket=189703 Order By OccurredOn Desc

这将返回2行：

select 1 as id
union
select 2 as id

这将返回1行：

select top 1 * from (
  select 1 as id
  union
  select 2 as id
) as x
order by id

---

列名无效。这很奇怪。查看返回的第1行或第2行，当然，在这个查询中没有定义。我也会编辑它来包含OP查询，但是看起来我只是从“juergen d”复制了答案。。。

select top 1 * from (
  select 1 as id
  union
  select 2 as id
) as x
order by id