--- title: Fulltext Search Indexes description: Fulltext index guide tags: mysql, fulltext, search, indexes, boolean-mode --- # Fulltext Indexes Fulltext indexes are useful for keyword text search in MySQL. For advanced ranking, fuzzy matching, or complex document search, prefer a dedicated search engine. ```sql ALTER TABLE articles ADD FULLTEXT INDEX ft_title_body (title, body); -- Natural language (default, sorted by relevance) SELECT *, MATCH(title, body) AGAINST('database performance') AS score FROM articles WHERE MATCH(title, body) AGAINST('database performance'); -- Boolean mode: + required, - excluded, * suffix wildcard, "exact phrase" WHERE MATCH(title, body) AGAINST('+mysql -postgres +optim*' IN BOOLEAN MODE); ``` ## Key Gotchas - **Min word length**: default 3 chars (`innodb_ft_min_token_size`). Shorter words are ignored. Changing this requires rebuilding the FULLTEXT index (drop/recreate) to take effect. - **Stopwords**: common words excluded. Control stopwords with `innodb_ft_enable_stopword` and customize via `innodb_ft_user_stopword_table` / `innodb_ft_server_stopword_table` (set before creating the index, then rebuild to apply changes). - **No partial matching**: unlike `LIKE '%term%'`, requires whole tokens (except `*` in boolean mode). - **MATCH() columns must correspond to an index definition**: `MATCH(title, body)` needs a FULLTEXT index that covers the same column set (e.g. `(title, body)`). - Boolean mode without required terms (no leading `+`) can match a very large portion of the index and be slow. - Fulltext adds write overhead — consider Elasticsearch/Meilisearch for complex search needs.