What is the Maximum Size of a MySQL VARCHAR Column, and What Factors Affect It?

MySQL VARCHAR Maximum Size Explained

The maximum size of a MySQL VARCHAR data type is a crucial consideration when designing your database. While the documentation mentions a row size limit of 65k, the specific maximum size depends on the MySQL version and character set used.

MySQL 5.0.3 and Earlier

Prior to MySQL 5.0.3, the maximum length of a VARCHAR column was limited to 255 characters. However, keep in mind that the row size limit of 65,535 bytes applies, including the VARCHAR column size.

MySQL 5.0.3 and Later

In MySQL 5.0.3 and subsequent versions, the maximum length of a VARCHAR column was extended to 65,535 characters. However, this limit is still subject to the overall row size limit and the character set used.

Multi-Byte Character Sets

Using multi-byte character sets like UTF-8 or UTF-8mb4 can reduce the maximum size of a VARCHAR column. For instance, UTF-8 stores each character using 1-4 bytes, while UTF-8mb4 uses 1-4 bytes for the Basic Multilingual Plane (BMP) characters and 4 bytes for characters outside the BMP.

Alternative Data Types

If you exceed the maximum VARCHAR size, consider using the TEXT data types (TINYTEXT, TEXT, MEDIUMTEXT, or LONGTEXT). These types offer larger storage capacities and are not subject to the row size limit. However, they may have performance implications depending on the use case.

Additional Resources

• [MySQL BLOB and TEXT Types](https://dev.mysql.com/doc/refman/8.0/en/blob.html)
• [MySQL Data Type Storage Requirements](https://dev.mysql.com/doc/refman/5.7/en/storage-requirements.html)

By understanding these limitations and considerations, you can determine the appropriate maximum size for your MySQL VARCHAR columns and design a database that meets your data storage needs efficiently.

The above is the detailed content of What is the Maximum Size of a MySQL VARCHAR Column, and What Factors Affect It?. For more information, please follow other related articles on the PHP Chinese website!