Question

我有一个像这样的表结构：

      table users
+-------+--------------+
| Field |     Type     |
+-------+--------------+
|   id  |      INT     |
+-------+--------------+
|  name | VARCHAR(255) |
+-------+--------------+

我希望单个查询在按字母顺序排序时应返回最长和最小的NAME以及它们各自的长度。

例如

假设数据是（它是假的）

ABA, BBA, PQR, HITS, QUES, PQRST, ABCDE

我希望查询返回

+-------+---+
|  ABA  | 3 |
+-------+---+
| ABCDE | 5 |
+-------+---+

我试过了：

(
SELECT minName, LENGTH(minName)
FROM (
    SELECT name AS minName 
    FROM users
    WHERE LENGTH(name)=(SELECT MIN(LENGTH(name)) FROM users)
    ) AS maxUsers
ORDER BY minName ASC
LIMIT 1
)
UNION
(
SELECT minName, LENGTH(minName)
FROM (
    SELECT name AS minName 
    FROM users
    WHERE LENGTH(name)=(SELECT MAX(LENGTH(name)) FROM users)
    ) AS maxUsers
ORDER BY minName ASC
LIMIT 1
)

如何简化此查询？任何人？

Answer 1

这是一个更简单的查询，它返回 all 具有最小和最大长度的名称：

SELECT u.Name, LENGTH(u.Name) as len
FROM users u JOIN
     (SELECT MIN(LENGTH(Name)) as minl, MAX(LENGTH(Name)) as maxl
      FROM users u
     ) uu
     ON LENGTH(u.name) IN (uu.minl, uu.maxl);

你想要每个长度中的一个。您可以使用其他聚合来获取此信息：

SELECT MIN(u.Name) as Name, LENGTH(u.Name) as len
FROM users u JOIN
     (SELECT MIN(LENGTH(Name)) as minl, MAX(LENGTH(Name)) as maxl
      FROM users u
     ) uu
     ON LENGTH(u.name) IN (uu.minl, uu.maxl)
GROUP BY LENGTH(u.Name);

Answer 2

如果你想使用UNION试试这个

(
    SELECT 
       name,
       LENGTH(name)
    FROM users
    ORDER BY LENGTH(name), name ASC
    LIMIT 1
)
UNION
(
    SELECT 
       name,
       LENGTH(name)
    FROM users
    ORDER BY LENGTH(name) DESC, name ASC
    LIMIT 1
)

Answer 3

试试这个：更简单，更容易〜

最短的

SELECT MIN(name), LENGTH(MIN(name)) FROM users WHERE LENGTH(name)=(SELECT MIN(LENGTH(name)) FROM users);

最长的

SELECT MAX(name), LENGTH(MAX(name)) FROM users WHERE LENGTH(name)=(SELECT MAX(LENGTH(name)) FROM users);

Answer 4

许多解决方案提供了一个由多个子查询组成的解决方案，这给SQL初学者带来了很多困惑。这是一个不太复杂的解决方案-

SELECT * FROM (
                  SELECT <COL_NAME>,LENGTH(<COL_NAME>) AS Length FROM <TABLE_NAME> 
                  ORDER BY 2,1 LIMIT 1
                  ) as MINIMUM 

    UNION ALL 

    SELECT * FROM (
                   SELECT <COL_NAME>,LENGTH(<COL_NAME>) AS Length FROM <TABLE_NAME> 
                   ORDER BY 2 DESC,1 LIMIT 1
                  ) as MAXIMUM;

在MYSQL中按字母顺序排序的SHORTEST和LONGEST字符串是什么？

4 个答案: