Question

假设我在SQL Server中有一个表Station：

|  ID  | Name |
+------+------+
|  1   | a    |
|  2   | b    |
|  3   | cc   |
|  4   | ddd  |
|  5   | eee  |

我想检索最短和最长的名称以及长度（如果是平局，它将按字母顺序显示前1）所以，输出将是

|  a  |   1  |
+-----+------+
| ddd |   3  |

我试过了：

Select  
    Name, len(name) 
from 
    Station 
where 
    len(name) = (Select min(len(name)) from Station) 
union

Select  
    Name, len(name) 
from 
    Station 
where 
    len(name) = (Select max(len(name)) from Station)

但是，我必须先按字母顺序排在第一位，这是我无法做到的

Answer 1

SELECT *
FROM
    (SELECT TOP(1) *, LEN(name) as ln
    FROM Student
    ORDER BY ln, name
    UNION
    SELECT TOP(1) *, LEN(name) as ln
    FROM Student
    ORDER BY ln DESC, name) as tblMain

Answer 2

select  *
from    (
        select  name
        ,       row_number() over (order by len(name), name) rn1
        ,       row_number() over (order by len(name) desc, name) rn2
        from    student
        ) sub
where   rn1 = 1  -- Shortest name
        or rn2 = 1  -- Longest name

Answer 3

您的方法可以轻微调整：

Select  min(Name) as name, len(name)
from Station 
where len(name) = (Select min(len(name)) from Station) 
group by len(name)
union all
Select min(Name) as name, len(name)
from Station 
where len(name) = (Select max(len(name)) from Station) 
group by len(name);

或：

Select min(Name) as name, min(len(name))
from Station 
where len(name) = (Select min(len(name)) from Station) 
union all
Select min(Name) as name, min(len(name))
from Station 
where len(name) = (Select max(len(name)) from Station) ;

也就是说，通过聚合，你得到一行。

如何从表中获取最短和最长的字符串？

3 个答案: