MySQL 查询字段的最短和最长长度

Question

问题

我需要从数据库中return最短和最长的城市名称及其各自的长度。我也欢迎改进此查询以使其更优雅。

SQL Fiddle

到目前为止，我有一个示例数据库和查询： http://sqlfiddle.com/#!9/3b4a7c/1/0

查询

SELECT DISTINCT City, LENGTH(City) as len
FROM STATION
WHERE LENGTH(City)=(SELECT MIN(LENGTH(City)) FROM STATION) 
OR LENGTH(City)=(SELECT MAX(LENGTH(City)) FROM STATION)
ORDER BY len

当前结果

Dole    4
Reus    4
Sant'Egidio del Monte Albino    28

想要的结果

Dole    4
Sant'Egidio del Monte Albino    28

Answer 1

我会使用 union all、order by 和 limit 来做到这一点。 . .如果你只想要一个最长和最短名字的例子：

(select city, length(city)
 from station
 order by length(city) asc
 limit 1
) union all
(select city, length(city)
 from station
 order by length(city) desc
 limit 1
);

如果你想要联系，当不止一个城市匹配时，我会这样做：

select s.city, length(s.city)
from station s cross join
     (select max(length(city)) as maxl, min(length(city)) as minl
      from station
     ) ss
where length(s.city) in (ss.minl, ss.maxl);

Answer 2

select min(a.city),length(a.city)
from station a
join (SELECT min(length(city)) minlength,max(length(city)) maxlength from station) b
on length(a.city) in (minlength,maxlength)
group by length(a.city)

MySQL 查询字段的最短和最长长度

MySQL query for shortest & longest length of a field

mysql

aggregate-functions

问题

SQL Fiddle

查询

当前结果

想要的结果