顺序顺序应用在并集之后，所以 在语句的末尾添加一个order by子句:

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

顺序顺序应用在并集之后，所以 在语句的末尾添加一个order by子句:

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

为什么不用TOP X呢?

SELECT pass1.* FROM 
 (SELECT TOP 2000000 tblA.ID, tblA.CustomerName 
  FROM TABLE_A AS tblA ORDER BY 2) AS pass1
UNION ALL 
SELECT pass2.* FROM 
  (SELECT TOP 2000000 tblB.ID, tblB.CustomerName 
   FROM TABLE_B AS tblB ORDER BY 2) AS pass2

TOP 2000000是一个任意的数字，它大到足以捕获所有的数据。根据您的要求进行调整。

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

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);