MySQL FULLTEXT Indexes

`FULLTEXT` indexes in MySQL are used to perform full-text searches on columns containing textual data. This type of index allows for efficient searching of words or phrases within large text fields, such as those found in articles or product descriptions.

Usage

`FULLTEXT` indexes are particularly useful when you need to implement search functionality that requires finding specific words or phrases within text columns. They are applied to `CHAR`, `VARCHAR`, or `TEXT` columns, enabling full-text searches using the `MATCH ... AGAINST` syntax.

CREATE FULLTEXT INDEX index_name
ON table_name (column1, column2, ...);

In this syntax, `CREATE FULLTEXT INDEX` creates a full-text index on the specified columns of the table.

Examples

1. Creating a FULLTEXT Index

CREATE FULLTEXT INDEX idx_article_title
ON articles (title);

This example creates a `FULLTEXT` index on the `title` column of the `articles` table, allowing for efficient text searches on article titles.

2. Basic FULLTEXT Search

SELECT * FROM articles
WHERE MATCH(title) AGAINST('MySQL indexing');

Here, the `MATCH ... AGAINST` clause is used to search the `articles` table for records where the `title` column contains the phrase "MySQL indexing".

3. FULLTEXT Search with Boolean Mode

SELECT * FROM articles
WHERE MATCH(content) AGAINST('+MySQL -indexing' IN BOOLEAN MODE);

This example performs a boolean mode search, retrieving articles whose `content` contains the word "MySQL" but not "indexing".

4. FULLTEXT Search with Other Boolean Operators

SELECT * FROM articles
WHERE MATCH(content) AGAINST('MySQL* >5 <10' IN BOOLEAN MODE);

This example uses additional boolean operators: `*` for wildcard matching, `>` and `<` to adjust the relevance of the search terms.

Tips and Best Practices

• Use `FULLTEXT` for large text data. It is most beneficial for columns with substantial text content, offering significant performance improvements over `LIKE` queries.
• Combine with `MATCH ... AGAINST`. Always use `MATCH ... AGAINST` for executing full-text searches to leverage the index properly.
• Consider the table storage engine. Ensure that your table uses a storage engine that supports `FULLTEXT`, such as InnoDB or MyISAM.
• Optimize search queries. Use boolean mode for more complex search logic, like including or excluding specific words.
• Analyze the need. Implement `FULLTEXT` indexes only where necessary, as they can increase storage requirements.
• Rebuild indexes as needed. Regularly rebuild indexes after significant data changes to maintain optimal performance.
• Understand limitations. Be aware of the minimum word length for indexing and default stopwords that may be ignored.
• Performance considerations. Frequently updating indexed columns can affect performance — consider batch updates if possible.
• Explore search modes. `NATURAL LANGUAGE MODE` provides relevance-based results without boolean operators, differing from `BOOLEAN MODE`.

Version-specific Differences

Note that `FULLTEXT` support and features have evolved over different MySQL versions. Check for version-specific differences or enhancements for your specific MySQL version.