What is the Maximum VARCHAR Size in MySQL and What Factors Affect It?

Understanding MySQL VARCHAR Maximum Size

MySQL VARCHAR data type allows storage of variable-length strings. While the row size limit of 65k may appear to limit the VARCHAR size, the actual maximum size varies based on MySQL version and character set.

VARCHAR Size Limitations

• MySQL versions before 5.0.3: VARCHAR size can range from 0 to 255 characters.
• MySQL versions 5.0.3 and later: VARCHAR size can range from 0 to 65,535 characters.

Row Size Limitation

The actual size of a VARCHAR column is constrained by the row size limit of 65,535 bytes. This means that the total size of all columns in a row cannot exceed 65,535 bytes.

Character Set Impact

The character set used also affects the maximum VARCHAR size. For example, UTF-8 will use more bytes per character than ASCII, which reduces the effective maximum size for VARCHAR.

Using TEXT Types

To overcome the row size limit, MySQL provides TEXT types (TINYTEXT, TEXT, MEDIUMTEXT, LONGTEXT) that allow storage of larger text content. These types are stored separately from the rest of the row, reducing the impact on the row size limit.

Conclusion

The maximum size for a MySQL VARCHAR column depends on the MySQL version, character set, and row size limit. While VARCHAR sizes can reach up to 65,535 characters in MySQL 5.0.3 and later, careful consideration of character set and row size limitations is necessary to ensure data integrity.

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