当数据来自许多选择和联合在一起时,是否有可能进行排序?如

Select id,name,age
From Student
Where age < 15
Union
Select id,name,age
From Student
Where Name like "%a%"

如何按名称对此查询进行排序?

我试过了

Select id,name,age
From Student
Where age < 15 or name like "%a%"
Order by name

但这并不奏效。


当前回答

只写

Select id,name,age
From Student
Where age < 15
Union
Select id,name,age
From Student
Where Name like "%a%"
Order by name

顺序被应用到完整的结果集

其他回答

要将ORDER BY或LIMIT子句应用于单个SELECT,请将SELECT子句插入圆括号内:

(SELECT a FROM t1 WHERE a=10 AND B=1 ORDER BY a LIMIT 10)
UNION
(SELECT a FROM t2 WHERE a=11 AND B=2 ORDER BY a LIMIT 10);

Select id,name,age
from
(
   Select id,name,age
   From Student
   Where age < 15
  Union
   Select id,name,age
   From Student
   Where Name like "%a%"
) results
order by name

可以用这个:

Select id,name,age
From Student
Where age < 15
Union ALL
SELECT * FROM (Select id,name,age
From Student
Where Name like "%a%")

只写

Select id,name,age
From Student
Where age < 15
Union
Select id,name,age
From Student
Where Name like "%a%"
Order by name

顺序被应用到完整的结果集

为了使排序只适用于UNION中的第一个语句,你可以把它放在一个带有UNION ALL的子选择中(这两个在Oracle中都是必要的):

Select id,name,age FROM 
(    
 Select id,name,age
 From Student
 Where age < 15
 Order by name
)
UNION ALL
Select id,name,age
From Student
Where Name like "%a%"

或者(针对Nicholas Carey的评论)你可以保证顶部的SELECT是有序的,结果显示在下面的SELECT上面,就像这样:

Select id,name,age, 1 as rowOrder
From Student
Where age < 15
UNION
Select id,name,age, 2 as rowOrder
From Student
Where Name like "%a%"
Order by rowOrder, name