sql - Oracle FETCH FIRST 1 ROW with UNION ALL 语句

Question

我正在尝试使用 FETCH FIRST 1 ROW 在 SQL 中创建一个 UNION ALL 语句，但是当我这样做时它给我一个错误 MISSING KEYWORD

这是我的 SQL 的样子:

Select * From tabl1 where Date = '04-MAR-2020' FETCH FIRST 1 ROW

UNION ALL

Select * From tabl1 where Date = '05-MAR-2020' FETCH FIRST 1 ROW

是这样可行的。我想将其保留为单个语句，而不是添加 SUBQUERY 或任何类似性质的内容。

Answer 1

只需将每个部分放在括号中即可。无论如何，在 12.2 中工作:

( Select * From tabl1 where Date = '04-MAR-2020' FETCH FIRST 1 ROW )
UNION ALL
( Select * From tabl1 where Date = '05-MAR-2020' FETCH FIRST 1 ROW )

对于任何感兴趣的人，我的实际测试查询是这样的:

(select   object_name 
 from     user_objects 
 where    object_type = 'TABLE' 
 order by object_name 
 fetch first 1 row only)
UNION ALL
(select   object_name 
 from     user_objects 
 where    object_type = 'VIEW' 
 order by object_name 
 fetch first 1 row only);