如何为Union结果添加订单？

Question

在SQL Server 2008中，我们可以使用Union / Unino All将两个结果放在一起，但我想为最终结果添加order by。怎么办？

我想要的是：

select id1 as id, * from ...
Union All
select id2 as id, * from ...
order by id

请帮助。谢谢。

Answer 1

如评论中所述，您提供的伪代码应该有效，将顺序应用于组合结果集。如果您尝试以两种结果集保持不同的方式进行排序，则需要引入人工排序列，例如：

select id1 as id, *, 1 as MySortKey from ...
Union All
select id2 as id, *, 2 as MySortKey from ...
order by MySortKey, id

Answer 2

您也可以使用此查询

select * from (
select id1 as id, * from ...
Union All
select id2 as id, * from ...
) aaaa
order by id

Answer 3

使用此代码：

Select * from 
(select id1 as id, * from ...
Union All
select id2 ad id,  * from ...
order by id) as t
order by t.id

Answer 4

使用northwind

select OrderID, ProductID from [Order Details] a
UNION all
Select OrderID, EmployeeID from Orders b
order by a.ProductID

Answer 5

所有这些答案都包括原始海报的尝试只是简单的混乱或过于复杂。这里有一个简单易懂的解释：

How to order by with union

with，

“只需​​写下

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

order by应用于完整的结果集 “ 只需在这里使用UNION ALL而不是UNION。