MySQL VARCHAR 长度和 UTF-8

Question

在 MySQL 中，如果我在 UTF-8 表中创建一个新的 VARCHAR(32) 字段是否意味着我可以在该字段中存储 32 个字节的数据或 32 个字符(多字节) ？

Answer 1

这个答案出现在我的谷歌搜索结果的顶部，但不正确。

困惑可能是由于测试的 MySQL 版本不同。

• 版本 4 计算字节数
• 版本 5 计算字符数

这里引用自官方 MySQL 5 documentation :

MySQL interprets length specifications in character column definitions in character units. (Before MySQL 4.1, column lengths were interpreted in bytes.) This applies to CHAR, VARCHAR, and the TEXT types.

有趣的是(我没想到)varchar 列的最大长度受 utf8 影响如下:

The effective maximum length of a VARCHAR in MySQL 5.0.3 and later is subject to the maximum row size (65,535 bytes, which is shared among all columns) and the character set used. For example, utf8 characters can require up to three bytes per character, so a VARCHAR column that uses the utf8 character set can be declared to be a maximum of 21,844 characters.