如何在MySQL CREATE TABLE查询中使用CHAR_LENGTH()？

在创建表格时，使用CHAR_LENGTH(yourColumnName)。让我们先看一个例子并创建一个表格 −

mysql> create table DemoTable
    (
    Id int NOT NULL AUTO_INCREMENT PRIMARY KEY,
    Title varchar(200),
    `Number_of_characters` int as (char_length(Title))
    );
Query OK, 0 rows affected (0.18 sec)

使用INSERT命令在表格中插入一些记录 −

mysql> insert into DemoTable(Title) values('Introduction To MySQL');
Query OK, 1 row affected (0.06 sec)

mysql> insert into DemoTable(Title) values('Introduction To Java');
Query OK, 1 row affected (0.06 sec)

mysql> insert into DemoTable(Title) values('Introduction To MongoDB');
Query OK, 1 row affected (0.04 sec)

使用SELECT语句从表格中显示所有记录−

mysql> select *from DemoTable;

这将生成以下输出 −

+----+-------------------------+----------------------+
| Id | Title                   | Number_of_characters |
+----+-------------------------+----------------------+
| 1  | Introduction To MySQL   | 21                   |
| 2  | Introduction To Java    | 20                   |
| 3  | Introduction To MongoDB | 23                   |
+----+-------------------------+----------------------+
3 rows in set (0.00 sec)

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