如何在 MySQL 中获取最长的 VarChar 长度?
mysqlmysqli database更新于 2025/5/30 21:00:17
要获取最长的 varchar 长度，您需要使用 CHAR_LENGTH()。
语法如下
SELECT Max(CHAR_LENGTH(yourColumnName)) AS anyAliasName FROM yourTableName;
为了理解上述语法，让我们创建一个表。创建表的查询如下
mysql> create table CharLengthDemo - > ( - > Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, - > Sentence varchar(255) - > ); Query OK, 0 rows affected (0.60 sec)
使用 insert 命令在表中插入一些记录。
查询如下
mysql> insert into CharLengthDemo(Sentence) values('Java is an object oriented programming language'
- > );
Query OK, 1 row affected (0.45 sec)
mysql> insert into CharLengthDemo(Sentence) values('MySQL is a Relational Database Management System');
Query OK, 1 row affected (0.26 sec)
mysql> insert into CharLengthDemo(Sentence) values('JSP uses Java Programming Language');
Query OK, 1 row affected (0.24 sec)
mysql> insert into CharLengthDemo(Sentence) values('Object is a root class in java');
Query OK, 1 row affected (0.12 sec)
使用 select 语句显示表中的所有记录。
查询如下
mysql> select *from CharLengthDemo;
以下是输出 −
+----+--------------------------------------------------+ | Id | Sentence | +----+--------------------------------------------------+ | 1 | Java is an object oriented programming language | | 2 | MySQL is a Relational Database Management System | | 3 | JSP uses Java Programming Language | | 4 | Object is a root class in java | +----+--------------------------------------------------+ 4 rows in set (0.00 sec)
以下是获取最长 varchar 长度的查询
mysql> SELECT Max(CHAR_LENGTH(Sentence)) AS MAXLENGTH FROM CharLengthDemo;
以下是显示最长 varchar 长度的值的输出
+-----------+ | MAXLENGTH | +-----------+ | 48 | +-----------+ 1 row in set (0.00 sec)
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有用资源
mysql 参考教程 - 该教程包含有关 mysql 的更多信息:https://www.cainiaomax.com/mysql/
