订购工会

Question

两侧，我需要通过city订购union查询的两面：

select * from(select top(1)city, len(city) from Station  
where len(city) = (select min(len(d.city)) from Station d) order by city) as a 
union all select * from (select top(1) city, LEN(city) from Station 
where len(city) = (select max(len(f.city)) from station f) order by city) as b 

我需要订购两侧，因为如果我有相同长度的两个城市，然后我需要得到第一个按字母顺序，如果我把order by在整个查询结束它不会做我想要的，如果你有另一种方式做到这一点，我将不胜感激的建议..

当我运行这个查询我收到此错误：

Msg 8155, Level 16, State 2, Line 3 
No column name was specified for column 2 of 'a'. 
Msg 8155, Level 16, State 2, Line 4 
No column name was specified for column 2 of 'b'. 

我该怎么办？

Answer 1

select * from (select top(1) city, len(city) as 'length' 
       from Station  
       order by len(city) asc, city) as a 
union all 
select * from (select top(1) city, len(city) as 'length' 
       from Station  
       order by len(city) desc, city) as b 

Answer 2

固定

select * from(select top(1)city, len(city) as 'length' from Station  
where len(city) = (select min(len(d.city)) from Station d) order by city) as a 
union all select * from (select top(1) city, LEN(city) as 'length' from Station 
where len(city) = (select max(len(f.city)) from station f) order by city) as b 

Answer 3

先为LEN（市）

像指定列len(city) as lencity

，并且不要在这两个语句顺序，不作任何difference..Its最后的订单由重要的..和秩序是不需要在总和

所以你的发言可以..

select * from(select top(1)city, len(city) as lencity 
from Station  
where len(city) = (select min(len(d.city)) from Station d)) as a 
union all 
select * from (select top(1) city, LEN(city) as lencity from Station 
where len(city) = (select max(len(f.city)) from station f) ) as b 
order by lencity