Difference Between TEXT and LONGTEXT in MySQL

Posted on by user

MySQL’s TEXT and LONGTEXT data types are both used to store large text data, but they differ in terms of maximum storage size and use cases.

1. Key Differences Between TEXT and LONGTEXT

Data TypeMaximum SizeStorage UsageTypical Use Cases
TEXT65,535 bytes (64KB)Up to 64KBArticles, comments, descriptions, emails
LONGTEXT4,294,967,295 bytes (4GB)Up to 4GBFull books, logs, large HTML data, JSON

Storage Details:

  • TEXT can store up to 64KB (including a 16-bit length prefix).
  • LONGTEXT can store up to 4GB (including a 32-bit length prefix).

2. When to Use TEXT

Best suited for:

  • Articles, blog posts, and user comments.
  • Product descriptions or metadata.
  • Email bodies and other moderately long text.

Why choose TEXT?

  • 64KB (around 60,000 characters) is sufficient for most text-based use cases.
  • It consumes less memory than LONGTEXT.

3. When to Use LONGTEXT

Best suited for:

  • Full books, research papers, or extensive documents.
  • Large HTML or JSON data storage.
  • Application logs (especially unstructured ones).

Why choose LONGTEXT?

  • If TEXT is insufficient, and the data size can exceed 64KB.
  • If even MEDIUMTEXT (16MB max) is not enough.

4. Considerations and Caveats

① Indexing Limitations

  • TEXT and LONGTEXT cannot be indexed normally, except for FULLTEXT indexes.
  • Searching within these fields using LIKE or SUBSTRING_INDEX() can be slow.

② Memory Consumption

  • Both TEXT and LONGTEXT store data externally, with only a pointer stored in the table row.
  • Excessive use of LONGTEXT can significantly slow down queries.

③ Restrictions with GROUP BY and ORDER BY

  • TEXT and LONGTEXT cannot be directly used in GROUP BY or ORDER BY. SELECT * FROM articles ORDER BY CAST(content AS CHAR) ASC;

④ Use FULLTEXT INDEX for Large Text Search

  • To improve search performance within LONGTEXT, use FULLTEXT indexes. ALTER TABLE articles ADD FULLTEXT INDEX(content); SELECT * FROM articles WHERE MATCH(content) AGAINST('MySQL');

5. Summary: Which One Should You Use?

ScenarioRecommended Data Type
Text size up to a few thousand charactersTEXT
Data exceeding several MBLONGTEXT
Full-text search neededTEXT or LONGTEXT (with FULLTEXT INDEX)
Performance is a priorityTEXT (smaller data leads to faster queries)

General Rule: Use TEXT Unless You Absolutely Need LONGTEXT

For MySQL performance reasons, it’s better to use TEXT whenever possible and only use LONGTEXT when absolutely necessary.