# Source: https://docs.lancedb.com/search/full-text-search.md

> ## Documentation Index
> Fetch the complete documentation index at: https://docs.lancedb.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Full-Text Search (FTS)

> Learn how to implement full-text search in LanceDB using BM25 for keyword-based retrieval.

export const PyFtsPostfiltering = "table.search(\"puppy\").limit(10).where(\"text='foo'\", prefilter=False).to_list()\n";

export const PyFtsPrefiltering = "table.search(\"puppy\").limit(10).where(\"text='foo'\", prefilter=True).to_list()\n";

LanceDB provides support for Full-Text Search via Lance, allowing you to incorporate keyword-based search (based on BM25) in your retrieval solutions.

## Basic Usage

Consider that we have a LanceDB table named `my_table`, whose string column `text` we want to index and query via keyword search, the FTS index must be created before you can search via keywords.

### Table Setup

First, open or create the table you want to search:

<CodeGroup>
  ```python Python icon="python" theme={"theme":{"light":"vitesse-light","dark":"catppuccin-mocha"}}
  import lancedb
  from lancedb.index import FTS

  uri = "data/sample-lancedb"
  db = lancedb.connect(uri)

  table = db.create_table(
      "my_table_fts",
      data=[
          {"vector": [3.1, 4.1], "text": "Frodo was a happy puppy"},
          {"vector": [5.9, 26.5], "text": "There are several kittens playing"},
      ],
  )
  ```

  ```ts TypeScript icon="square-js" theme={"theme":{"light":"vitesse-light","dark":"catppuccin-mocha"}}
  import * as lancedb from "@lancedb/lancedb";
  const uri = "data/sample-lancedb"
  const db = await lancedb.connect(uri);

  const data = [
      { vector: [3.1, 4.1], text: "Frodo was a happy puppy" },
      { vector: [5.9, 26.5], text: "There are several kittens playing" },
  ];
  const tbl = await db.createTable("my_table", data, { mode: "overwrite" });
  {{< /code >}}

  {{< code language="rust" >}}
  let uri = "data/sample-lancedb";
  let db = connect(uri).execute().await?;
  let initial_data: Box<dyn RecordBatchReader + Send> = create_some_records()?;
  let tbl = db
      .create_table("my_table", initial_data)
      .execute()
      .await?;
  ```
</CodeGroup>

### Construct FTS Index

Create a full-text search index on your text column:

<CodeGroup>
  ```python Python icon="python" theme={"theme":{"light":"vitesse-light","dark":"catppuccin-mocha"}}
  table.create_fts_index("text")
  ```

  ```typescript TypeScript icon="square-js" theme={"theme":{"light":"vitesse-light","dark":"catppuccin-mocha"}}
  await tbl.createIndex("text", {
      config: lancedb.Index.fts(),
  });
  {{< /code >}}

  {{< code language="rust" >}}
  tbl
      .create_index(&["text"], Index::FTS(FtsIndexBuilder::default()))
      .execute()
      .await?;
  ```
</CodeGroup>

### Full-text Search

Perform full-text search and retrieve results:

<CodeGroup>
  ```python Python icon="python" theme={"theme":{"light":"vitesse-light","dark":"catppuccin-mocha"}}
  results = table.search("puppy")
      .limit(10)
      .select(["text"])
      .to_list()
  # [{'text': 'Frodo was a happy puppy', '_score': 0.6931471824645996}]
  ```

  ```typescript TypeScript icon="square-js" theme={"theme":{"light":"vitesse-light","dark":"catppuccin-mocha"}}
  const results = await tbl
      .search("puppy", "fts")
      .select(["text"])
      .limit(10)
      .toArray();
  ```

  ```rust Rust icon="Rust" theme={"theme":{"light":"vitesse-light","dark":"catppuccin-mocha"}}
  let results = tbl
      .query()
      .full_text_search(FullTextSearchQuery::new("puppy".to_owned()))
      .select(lancedb::query::Select::Columns(vec!["text".to_owned()]))
      .limit(10)
      .execute()
      .await?;
  ```
</CodeGroup>

The search is conducted on all indexed columns by default, so it's useful when there are multiple indexed columns.

If you want to specify which columns to search use `fts_columns="text"`

<Note>
  LanceDB automatically searches on the existing FTS index if the input to the search is of type `str`. If you provide a vector as input, LanceDB will search the ANN index instead.
</Note>

## Advanced Usage

### Tokenize Table Data

By default, the text is tokenized by splitting on punctuation and whitespaces, and would filter out words that are longer than 40 characters. All words are converted to lowercase.

Stemming is useful for improving search results by reducing words to their root form, e.g. "running" to "run". LanceDB supports stemming for multiple languages. You should set the `base_tokenizer` parameter rather than `tokenizer_name` because you cannot customize the tokenizer if `tokenizer_name` is specified.

For example, to enable stemming for English:

<CodeGroup>
  ```python Python icon="python" theme={"theme":{"light":"vitesse-light","dark":"catppuccin-mocha"}}
  table.create_fts_index("text", language="English", replace=True)
  ```
</CodeGroup>

The tokenizer is customizable, you can specify how the tokenizer splits the text, and how it filters out words, etc.

**Default index parameters:**

* `base_tokenizer`: `"simple"`
* `language`: English
* `with_position`: false
* `max_token_length`: 40
* `lower_case`: true
* `stem`: true
* `remove_stop_words`: true
* `ascii_folding`: true

For example, for language with accents, you can specify the tokenizer to use `ascii_folding` to remove accents, e.g. 'é' to 'e':

<CodeGroup>
  ```python Python icon="python" theme={"theme":{"light":"vitesse-light","dark":"catppuccin-mocha"}}
  table.create_fts_index(
          "text",
          language="French",
          stem=True,
          ascii_folding=True,
          replace=True,
      )
  ```
</CodeGroup>

### Filtering Options

LanceDB full text search supports to filter the search results by a condition, both pre-filtering and post-filtering are supported.

This can be invoked via the familiar `where` syntax.

With pre-filtering:

<CodeGroup>
  <CodeBlock filename="Python" language="python" icon="python">
    {PyFtsPrefiltering}
  </CodeBlock>

  ```typescript TypeScript icon="square-js" theme={"theme":{"light":"vitesse-light","dark":"catppuccin-mocha"}}
  await tbl
  .search("puppy")
  .select(["id", "doc"])
  .limit(10)
  .where("meta='foo'")
  .prefilter(true)
  .toArray();
  ```

  ```rust Rust icon="Rust" theme={"theme":{"light":"vitesse-light","dark":"catppuccin-mocha"}}
  table
      .query()
      .full_text_search(FullTextSearchQuery::new("puppy".to_owned()))
      .select(lancedb::query::Select::Columns(vec!["doc".to_owned()]))
      .limit(10)
      .only_if("meta='foo'")
      .execute()
      .await?;
  ```
</CodeGroup>

With post-filtering:

<CodeGroup>
  <CodeBlock filename="Python" language="python" icon="python">
    {PyFtsPostfiltering}
  </CodeBlock>

  ```typescript TypeScript icon="square-js" theme={"theme":{"light":"vitesse-light","dark":"catppuccin-mocha"}}
  await tbl
  .search("apple")
  .select(["id", "doc"])
  .limit(10)
  .where("meta='foo'")
  .prefilter(false)
  .toArray();
  ```

  ```rust Rust icon="Rust" theme={"theme":{"light":"vitesse-light","dark":"catppuccin-mocha"}}
  table
      .query()
      .full_text_search(FullTextSearchQuery::new(words[0].to_owned()))
      .select(lancedb::query::Select::Columns(vec!["doc".to_owned()]))
      .postfilter()
      .limit(10)
      .only_if("meta='foo'")
      .execute()
      .await?;
  ```
</CodeGroup>

### Phrase vs. Terms Queries

<Warning>
  Lance-based FTS doesn't support queries using boolean operators `OR`, `AND` in the search string.
</Warning>

For full-text search you can specify either a **phrase** query like `"the old man and the sea"`,
or a **terms** search query like `old man sea`.

To search for a phrase, the index must be created with `with_position=True` and `remove_stop_words=False`:

<CodeGroup>
  ```python Python icon="python" theme={"theme":{"light":"vitesse-light","dark":"catppuccin-mocha"}}
  table.create_fts_index("text", with_position=True, replace=True)
  ```
</CodeGroup>

This will allow you to search for phrases, but it will also significantly increase the index size and indexing time.

### Fuzzy Search

Fuzzy search allows you to find matches even when the search terms contain typos or slight variations.
LanceDB uses the classic [Levenshtein distance](https://en.wikipedia.org/wiki/Levenshtein_distance)
to find similar terms within a specified edit distance.

| Parameter       | Type | Default | Description                                                                                                                                                 |
| --------------- | ---- | ------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------- |
| fuzziness       | int  | 0       | Maximum edit distance allowed for each term. If not specified, automatically set based on term length: 0 for length ≤ 2, 1 for length ≤ 5, 2 for length > 5 |
| max\_expansions | int  | 50      | Maximum number of terms to consider for fuzzy matching. Higher values may improve recall but increase search time                                           |

Let's create a sample table and build full-text search indices to demonstrate
fuzzy search capabilities and relevance boosting features.

### Search for Substring

LanceDB supports searching for substrings in the text column, you can set the `base_tokenizer` parameter to `"ngram"` to enable this feature, and use the parameters `ngram_min_length` and `ngram_max_length` to control the length of the substrings:

| Parameter          | Type | Default | Description                                        |
| ------------------ | ---- | ------- | -------------------------------------------------- |
| ngram\_min\_length | int  | 3       | Minimum length of the n-grams to search for        |
| ngram\_max\_length | int  | 3       | Maximum length of the n-grams to search for        |
| prefix\_only       | bool | false   | Whether to only search for prefixes of the n-grams |

## Example: Fuzzy Search

### Generate Data

First, let's create a table with sample text data for testing fuzzy search:

<CodeGroup>
  ```python Python icon="python" theme={"theme":{"light":"vitesse-light","dark":"catppuccin-mocha"}}
  import lancedb
  import numpy as np
  import pandas as pd
  import random

  # Connect to LanceDB
  db = lancedb.connect(
      uri="db://your-project-slug",
      api_key="your-api-key",
      region="us-east-1"
  )

  # Generate sample data
  table_name = "fts-fuzzy-boosting-test"
  vectors = [np.random.randn(128) for _ in range(100)]
  text_nouns = ("puppy", "car")
  text2_nouns = ("rabbit", "girl", "monkey")
  verbs = ("runs", "hits", "jumps", "drives", "barfs")
  adv = ("crazily.", "dutifully.", "foolishly.", "merrily.", "occasionally.")
  adj = ("adorable", "clueless", "dirty", "odd", "stupid")

  # Generate random text combinations
  text = [
      " ".join([
          text_nouns[random.randrange(0, len(text_nouns))],
          verbs[random.randrange(0, 5)],
          adv[random.randrange(0, 5)],
          adj[random.randrange(0, 5)],
      ])
      for _ in range(100)
  ]
  text2 = [
      " ".join([
          text2_nouns[random.randrange(0, len(text2_nouns))],
          verbs[random.randrange(0, 5)],
          adv[random.randrange(0, 5)],
          adj[random.randrange(0, 5)],
      ])
      for _ in range(100)
  ]
  count = [random.randint(1, 10000) for _ in range(100)]
  ```

  ```typescript TypeScript icon="square-js" theme={"theme":{"light":"vitesse-light","dark":"catppuccin-mocha"}}
  import * as lancedb from "@lancedb/lancedb"

  const db = await lancedb.connect({
      uri: "db://your-project-slug",
      apiKey: "your-api-key",
      region: "us-east-1"
  });

  // Generate sample data
  const tableName = "fts-fuzzy-boosting-test-ts";
  const n = 100;
  const vectors = Array.from({ length: n }, () => 
      Array.from({ length: 128 }, () => Math.random() * 2 - 1)
  );

  const textNouns = ["puppy", "car"];
  const text2Nouns = ["rabbit", "girl", "monkey"];
  const verbs = ["runs", "hits", "jumps", "drives", "barfs"];
  const adverbs = ["crazily", "dutifully", "foolishly", "merrily", "occasionally"];
  const adjectives = ["adorable", "clueless", "dirty", "odd", "stupid"];

  // Generate random text combinations
  const generateText = (nouns: string[]) => {
      const noun = nouns[Math.floor(Math.random() * nouns.length)];
      const verb = verbs[Math.floor(Math.random() * verbs.length)];
      const adv = adverbs[Math.floor(Math.random() * adverbs.length)];
      const adj = adjectives[Math.floor(Math.random() * adjectives.length)];
      return `${noun} ${verb} ${adv} ${adj}`;
  };

  const text = Array.from({ length: n }, () => generateText(textNouns));
  const text2 = Array.from({ length: n }, () => generateText(text2Nouns));
  const count = Array.from({ length: n }, () => Math.floor(Math.random() * 10000) + 1);
  ```
</CodeGroup>

### Create Table

<CodeGroup>
  ```python Python icon="python" theme={"theme":{"light":"vitesse-light","dark":"catppuccin-mocha"}}
  # Create table with sample data
  table = db.create_table(
      table_name,
      data=pd.DataFrame({
          "vector": vectors,
          "id": [i % 2 for i in range(100)],
          "text": text,
          "text2": text2,
          "count": count,
      }),
      mode="overwrite"
  )
  ```

  ```typescript TypeScript icon="square-js" theme={"theme":{"light":"vitesse-light","dark":"catppuccin-mocha"}}
  // Create table with sample data
  const data = makeArrowTable(
      vectors.map((vector, i) => ({
          vector,
          id: i % 2,
          text: text[i],
          text2: text2[i],
          count: count[i],
      }))
  );

  const table = await db.createTable(tableName, data, { mode: "overwrite" });
  ```
</CodeGroup>

### Construct FTS Index

Create a full-text search index on the first text column:

<CodeGroup>
  ```python Python icon="python" theme={"theme":{"light":"vitesse-light","dark":"catppuccin-mocha"}}
  # Create FTS index on first text column
  table.create_fts_index("text")
  wait_for_index(table, "text_idx")
  ```

  ```typescript TypeScript icon="square-js" theme={"theme":{"light":"vitesse-light","dark":"catppuccin-mocha"}}
  // Create FTS index on first text column
  await table.createIndex("text", { config: Index.fts() });
  await waitForIndex(table, "text_idx");
  ```
</CodeGroup>

Then, create an index on the second text column:

<CodeGroup>
  ```python Python icon="python" theme={"theme":{"light":"vitesse-light","dark":"catppuccin-mocha"}}
  # Create FTS index on second text column
  table.create_fts_index("text2")
  wait_for_index(table, "text2_idx")
  ```

  ```typescript TypeScript icon="square-js" theme={"theme":{"light":"vitesse-light","dark":"catppuccin-mocha"}}
  // Create FTS index on second text column
  await table.createIndex("text2", { config: Index.fts() });
  await waitForIndex(table, "text2_idx");
  ```
</CodeGroup>

### Basic and Fuzzy Search

Now we can perform basic, fuzzy, and prefix match searches:

#### Basic Exact Search

<CodeGroup>
  ```python Python icon="python" theme={"theme":{"light":"vitesse-light","dark":"catppuccin-mocha"}}
  from lancedb.query import MatchQuery

  # Basic match (exact search)
  basic_match_results = (
      table.search(MatchQuery("crazily", "text"))
      .select(["id", "text"])
      .limit(100)
      .to_pandas()
  )
  ```

  ```typescript TypeScript icon="square-js" theme={"theme":{"light":"vitesse-light","dark":"catppuccin-mocha"}}
  import { MatchQuery } from "@lancedb/lancedb";

  // Basic match (exact search)
  const basicMatchResults = await table.query()
      .fullTextSearch(new MatchQuery("crazily", "text"))
      .select(["id", "text"])
      .limit(100)
      .toArray();
  ```
</CodeGroup>

#### Fuzzy Search with Typos

<CodeGroup>
  ```python Python icon="python" theme={"theme":{"light":"vitesse-light","dark":"catppuccin-mocha"}}
  # Fuzzy match (allows typos)
  fuzzy_results = (
      table.search(MatchQuery("craziou", "text", fuzziness=2))
      .select(["id", "text"])
      .limit(100)
      .to_pandas()
  )
  ```

  ```typescript TypeScript icon="square-js" theme={"theme":{"light":"vitesse-light","dark":"catppuccin-mocha"}}
  // Fuzzy match (allows typos)
  const fuzzyResults = await table.query()
      .fullTextSearch(new MatchQuery("craziou", "text", {
          fuzziness: 2,
      }))
      .select(["id", "text"])
      .limit(100)
      .toArray();
  ```
</CodeGroup>

#### Prefix based Match

Prefix-based match allows you to search for documents containing words that start with a specific prefix.

<CodeGroup>
  ```python Python icon="python" theme={"theme":{"light":"vitesse-light","dark":"catppuccin-mocha"}}
  # Fuzzy match (allows typos)
  fuzzy_results = (
      table.search(MatchQuery("cra", "text", prefix_length=3))
      .select(["id", "text"])
      .limit(100)
      .to_pandas()
  )
  ```

  ```typescript TypeScript icon="square-js" theme={"theme":{"light":"vitesse-light","dark":"catppuccin-mocha"}}
  // Fuzzy match (allows typos)
  const fuzzyResults = await table.query()
      .fullTextSearch(new MatchQuery("cra", "text", {
          prefixLength: 3,
      }))
      .select(["id", "text"])
      .limit(100)
      .toArray();
  ```
</CodeGroup>

### Phrase Match

Phrase matching enables you to search for exact sequences of words. Unlike regular text search
which matches individual terms independently, phrase matching requires words to appear in the
specified order with no intervening terms.

Phrase matching is particularly useful for:

* Searching for specific multi-word expressions
* Matching exact titles or quotes
* Finding precise word combinations in a specific order

<CodeGroup>
  ```python Python icon="python" theme={"theme":{"light":"vitesse-light","dark":"catppuccin-mocha"}}
  # Exact phrase match
  from lancedb.query import PhraseQuery

  print("\n1. Exact phrase match for 'puppy runs':")
  phrase_results = (
      table.search(PhraseQuery("puppy runs", "text"))
      .select(["id", "text"])
      .limit(100)
      .to_pandas()
  )
  ```

  ```typescript TypeScript icon="square-js" theme={"theme":{"light":"vitesse-light","dark":"catppuccin-mocha"}}
  import { PhraseQuery } from "@lancedb/lancedb";

  // Exact phrase match
  console.log("\n1. Exact phrase match for 'puppy runs':");
  const phraseResults = await table.query()
    .fullTextSearch(new PhraseQuery("puppy runs", "text"))
    .select(["id", "text"])
    .limit(100)
    .toArray();
  ```
</CodeGroup>

#### Flexible Phrase Match

To provide more flexible phrase matching, LanceDB supports the `slop` parameter. This allows you to match phrases where the terms appear close to each other, even if they are not directly adjacent or in the exact order, as long as they are within the specified `slop` value.

For example, the phrase query "puppy merrily" would not return any results by default. However, if you set `slop=1`, it will match phrases like "puppy jumps merrily", "puppy runs merrily", and similar variations where one word appears between "puppy" and "merrily".

<CodeGroup>
  ```python Python icon="python" theme={"theme":{"light":"vitesse-light","dark":"catppuccin-mocha"}}
  # Flexible phrase match with slop=1 for 'puppy merrily'
  from lancedb.query import PhraseQuery

  print("\n1. Flexible phrase match for 'puppy merrily' with slop=1:")
  phrase_results = (
      table.search(PhraseQuery("puppy merrily", "text", slop=1))
      .select(["id", "text"])
      .limit(100)
      .to_pandas()
  )
  ```

  ```typescript TypeScript icon="square-js" theme={"theme":{"light":"vitesse-light","dark":"catppuccin-mocha"}}
  import { PhraseQuery } from "@lancedb/lancedb";

  // Flexible phrase match with slop=1 for 'puppy runs'
  console.log("\n1. Flexible phrase match for 'puppy runs' with slop=1:");
  const phraseResults = await table.query()
    .fullTextSearch(new PhraseQuery("puppy runs", "text", { slop: 1 }))
    .select(["id", "text"])
    .limit(100)
    .toArray();
  ```
</CodeGroup>

### Search with Boosting

Boosting allows you to control the relative importance of different search terms or fields
in your queries. This feature is particularly useful when you need to:

* Prioritize matches in certain columns
* Promote specific terms while demoting others
* Fine-tune relevance scoring for better search results

| Parameter       | Type  | Default  | Description                                                        |
| --------------- | ----- | -------- | ------------------------------------------------------------------ |
| positive        | Query | required | The primary query terms to match and promote in results            |
| negative        | Query | required | Terms to demote in the search results                              |
| negative\_boost | float | 0.5      | Multiplier for negative matches (lower values = stronger demotion) |

<CodeGroup>
  ```python Python icon="python" theme={"theme":{"light":"vitesse-light","dark":"catppuccin-mocha"}}
  from lancedb.query import MatchQuery, BoostQuery, MultiMatchQuery

  # Boost data with 'runs' in text more than 'puppy' in text
  print("\n2. Boosting data with 'runs' in text:")
  boosting_results = (
    table.search(
        BoostQuery(
            MatchQuery("runs", "text"),
            MatchQuery("puppy", "text"),
            negative_boost=0.2,
        ),
    )
    .select(["id", "text"])
    .limit(100)
    .to_pandas()
  )

  """Test searching across multiple fields."""
  print("\n=== Multi Match Query Examples ===")
  # Search across both text and text2
  print("\n1. Searching 'crazily' in both text and text2:")
  multi_match_results = (
      table.search(MultiMatchQuery("crazily", ["text", "text2"]))
      .select(["id", "text", "text2"])
      .limit(100)
      .to_pandas()
  )

  # Search with field boosting
  print("\n2. Searching with boosted text2 field:")
  multi_match_boosting_results = (
      table.search(
          MultiMatchQuery("crazily", ["text", "text2"], boosts=[1.0, 2.0]),
      )
      .select(["id", "text", "text2"])
      .limit(100)
      .to_pandas()
  )
  ```

  ```typescript TypeScript icon="square-js" theme={"theme":{"light":"vitesse-light","dark":"catppuccin-mocha"}}
  import { MatchQuery, BoostQuery, MultiMatchQuery } from "@lancedb/lancedb";

  // Boosting Example
  console.log("\n2. Boosting data with 'runs' in text:");
  const boostingResults = await table.query()
    .fullTextSearch(new BoostQuery(new MatchQuery("runs", "text"), new MatchQuery("puppy", "text"), {
      negativeBoost: 0.2,
    }))
    .select(["id", "text"])
    .limit(100)
    .toArray();

  // Multi Match Query Examples
  console.log("\n=== Multi Match Query Examples ===");

  // Search across both text fields
  console.log("\n1. Searching 'crazily' in both text and text2:");
  const multiMatchResults = await table.query()
    .fullTextSearch(new MultiMatchQuery("crazily", ["text", "text2"]))
    .select(["id", "text", "text2"])
    .limit(100)
    .toArray();

  // Search with field boosting
  console.log("\n2. Searching with boosted text2 field:");
  const multiMatchBoostingResults = await table.query()
    .fullTextSearch(new MultiMatchQuery("crazily", ["text", "text2"], {
      boosts: [1.0, 2.0],
    }))
    .select(["id", "text", "text2"])
    .limit(100)
    .toArray();
  ```
</CodeGroup>

<Card title="Best practices" icon="flag">
  * Use fuzzy search when handling user input that may contain typos or variations
  * Apply field boosting to prioritize matches in more important columns
  * Combine fuzzy search with boosting for robust and precise search results

  **Recommendations for optimal FTS performance:**

  * Create full-text search indices on text columns that will be frequently searched
  * For hybrid search combining text and vectors, see our [hybrid search guide](/search/hybrid-search/)
  * For performance benchmarks, check our [benchmark results](/enterprise/benchmarks/)
  * For complex queries, use SQL to combine FTS with other filter conditions
</Card>

### Boolean Queries

LanceDB supports boolean logic in full-text search, allowing you to combine multiple queries using `and` and `or` operators. This is useful when you want to match documents that satisfy multiple conditions (intersection) or at least one of several conditions (union).

#### Combining Two Match Queries

In Python, you can combine two MatchQuery objects using either the `and` function or the `&` operator (e.g., `MatchQuery("puppy", "text") and MatchQuery("merrily", "text")`); both methods are supported and yield the same result. Similarly, you can use either the `or` function or the `|` operator to perform an or query.

In TypeScript, boolean queries are constructed using the `BooleanQuery` class with a list of \[Occur, subquery] pairs. For example, to perform an AND query:

```sql SQL icon="code" theme={"theme":{"light":"vitesse-light","dark":"catppuccin-mocha"}}
BooleanQuery([
[Occur.Must, new MatchQuery("puppy", "text")],
[Occur.Must, new MatchQuery("merrily", "text")],
])
```

This approach allows you to specify complex boolean logic by combining multiple subqueries with different Occur values (such as `Must`, `Should`, or `MustNot`).

<Info>
  **Which queries are allowed?**

  A boolean query must include at least one `SHOULD` or `MUST` clause. Queries that contain only a `MUST_NOT` clause are not allowed.
</Info>

<CodeGroup>
  ```python Python icon="python" theme={"theme":{"light":"vitesse-light","dark":"catppuccin-mocha"}}
  from lancedb.query import MatchQuery

  # Example: Find documents containing both "puppy" and "merrily"
  and_query = MatchQuery("puppy", "text") & MatchQuery("merrily", "text")
  and_results = (
      table.search(and_query)
      .select(["id", "text"])
      .limit(100)
      .to_pandas()
  )
  print("\nDocuments containing both 'puppy' and 'merrily':")
  print(and_results)

  # Example: Find documents containing either "puppy" or "merrily"
  or_query = MatchQuery("puppy", "text") | MatchQuery("merrily", "text")
  or_results = (
      table.search(or_query)
      .select(["id", "text"])
      .limit(100)
      .to_pandas()
  )
  print("\nDocuments containing either 'puppy' OR 'merrily':")
  print(or_results)
  ```

  ```typescript TypeScript icon="square-js" expandable=true theme={"theme":{"light":"vitesse-light","dark":"catppuccin-mocha"}}
  import { MatchQuery, BooleanQuery, Occur } from "@lancedb/lancedb";

  // Flexible boolean queries with MatchQuery

  // Find documents containing both "puppy" and "merrily"
  const mustResults = await table
      .search(
        new BooleanQuery([
          [Occur.Must, new MatchQuery("puppy", "text")],
          [Occur.Must, new MatchQuery("merrily", "text")],
        ]),
      )
      .select(["id", "text"])
      .limit(100)
      .toArray();
  console.log("\nDocuments containing both 'puppy' and 'merrily':");
  console.log(mustResults);

  // Find documents containing either "puppy" or "merrily"
  const shouldResults = await table
      .search(
        new BooleanQuery([
          [Occur.Should, new MatchQuery("puppy", "text")],
          [Occur.Should, new MatchQuery("merrily", "text")],
        ]),
      )
      .select(["id", "text"])
      .limit(100)
      .toArray();
  console.log("\nDocuments containing either 'puppy' or 'merrily':");
  console.log(shouldResults);
  ```
</CodeGroup>

<Info>
  **How to use booleans?**

  * Use `and`/`&`(Python), `Occur.Must`(Typescript) for intersection (documents must match all queries).
  * Use `or`/`|`(Python), `Occur.Should`(Typescript) for union (documents must match at least one query).
</Info>

## Example: Substring Search

LanceDB supports searching for substrings in text columns using n-gram tokenization. This is useful for finding partial matches within text content.

### Setting Up the Table

First, create a table with sample text data and configure n-gram tokenization:

<CodeGroup>
  ```python Python icon="python" theme={"theme":{"light":"vitesse-light","dark":"catppuccin-mocha"}}
  import pyarrow as pa
  import lancedb

  db = lancedb.connect(":memory:")

  data = pa.table({"text": ["hello world", "lance database", "lance is cool"]})
  table = db.create_table("test", data=data)
  table.create_fts_index("text", base_tokenizer="ngram")
  ```
</CodeGroup>

### Basic Substring Search

With the default n-gram settings (minimum length of 3), you can search for substrings of length 3 or more:

<CodeGroup>
  ```python Python icon="python" theme={"theme":{"light":"vitesse-light","dark":"catppuccin-mocha"}}
  results = table.search("lan", query_type="fts").limit(10).to_list()
  assert len(results) == 2
  assert set(r["text"] for r in results) == {"lance database", "lance is cool"}

  results = (
      table.search("nce", query_type="fts").limit(10).to_list()
  )  # spellchecker:disable-line
  assert len(results) == 2
  assert set(r["text"] for r in results) == {"lance database", "lance is cool"}
  ```
</CodeGroup>

### Handling Short Substrings

By default, the minimum n-gram length is 3, so shorter substrings like "la" won't match:

<CodeGroup>
  ```python Python icon="python" theme={"theme":{"light":"vitesse-light","dark":"catppuccin-mocha"}}
  results = table.search("la", query_type="fts").limit(10).to_list()
  assert len(results) == 0
  ```
</CodeGroup>

### Customizing N-gram Parameters

You can customize the n-gram behavior by adjusting the minimum length and using prefix-only matching:

<CodeGroup>
  ```python Python icon="python" theme={"theme":{"light":"vitesse-light","dark":"catppuccin-mocha"}}
  table.create_fts_index(
      "text",
      base_tokenizer="ngram",
      replace=True,
      ngram_min_length=2,
      prefix_only=True,
  )
  ```
</CodeGroup>

### Testing Custom N-gram Settings

With the new settings, you can now search for shorter substrings and use prefix-only matching:

<CodeGroup>
  ```python Python icon="python" theme={"theme":{"light":"vitesse-light","dark":"catppuccin-mocha"}}
  results = table.search("lan", query_type="fts").limit(10).to_list()
  assert len(results) == 2
  assert set(r["text"] for r in results) == {"lance database", "lance is cool"}

  results = (
      table.search("nce", query_type="fts").limit(10).to_list()
  )  # spellchecker:disable-line
  assert len(results) == 0

  results = table.search("la", query_type="fts").limit(10).to_list()
  assert len(results) == 2
  assert set(r["text"] for r in results) == {"lance database", "lance is cool"}
  ```
</CodeGroup>

## Full-Text Search on Array Fields

LanceDB supports full-text search on string array columns, enabling efficient keyword-based search across multiple values within a single field (e.g., tags, keywords).

### Setting Up the Connection

Connect to your LanceDB instance:

<CodeGroup>
  ```python Python icon="python" theme={"theme":{"light":"vitesse-light","dark":"catppuccin-mocha"}}
  import lancedb

  # Connect to LanceDB
  db = lancedb.connect(
    uri="db://your-project-slug",
    api_key="your-api-key",
    region="us-east-1"
  )
  ```

  ```typescript TypeScript icon="square-js" expandable=true theme={"theme":{"light":"vitesse-light","dark":"catppuccin-mocha"}}
  import * as lancedb from "@lancedb/lancedb"

  const db = await lancedb.connect({
    uri: "db://your-project-slug",
    apiKey: "your-api-key",
    region: "us-east-1"
  });
  ```
</CodeGroup>

### Defining the Schema

Create a schema that includes an array field for tags:

<CodeGroup>
  ```python Python icon="python" theme={"theme":{"light":"vitesse-light","dark":"catppuccin-mocha"}}
  table_name = "fts-array-field-test"
  schema = pa.schema([
      pa.field("id", pa.string()),
      pa.field("tags", pa.list_(pa.string())),
      pa.field("description", pa.string())
  ])
  ```

  ```typescript TypeScript icon="square-js" expandable=true theme={"theme":{"light":"vitesse-light","dark":"catppuccin-mocha"}}
  const tableName = "fts-array-field-test-ts";

  // Create schema
  const schema = new Schema([
    new Field("id", new Utf8(), false),
    new Field("tags", new List(new Field("item", new Utf8()))),
    new Field("description", new Utf8(), false)
  ]);
  ```
</CodeGroup>

### Creating Sample Data

Generate sample data with array fields containing tags:

<CodeGroup>
  ```python Python icon="python" expandable=true theme={"theme":{"light":"vitesse-light","dark":"catppuccin-mocha"}}
  # Generate sample data
  data = {
      "id": [f"doc_{i}" for i in range(10)],
      "tags": [
          ["python", "machine learning", "data science"],
          ["deep learning", "neural networks", "AI"],
          ["database", "indexing", "search"],
          ["vector search", "embeddings", "AI"],
          ["full text search", "indexing", "database"],
          ["python", "web development", "flask"],
          ["machine learning", "deep learning", "pytorch"],
          ["database", "SQL", "postgresql"],
          ["search engine", "elasticsearch", "indexing"],
          ["AI", "transformers", "NLP"]
      ],
      "description": [
          "Python for data science projects",
          "Deep learning fundamentals",
          "Database indexing techniques",
          "Vector search implementations",
          "Full-text search guide",
          "Web development with Python",
          "Machine learning with PyTorch",
          "Database management systems",
          "Search engine optimization",
          "AI and NLP applications"
      ]
  }
  ```

  ```typescript TypeScript icon="square-js" expandable=true theme={"theme":{"light":"vitesse-light","dark":"catppuccin-mocha"}}
  // Generate sample data
  const data = makeArrowTable(
    Array(10).fill(0).map((_, i) => ({
      id: `doc_${i}`,
      tags: [
        ["python", "machine learning", "data science"],
        ["deep learning", "neural networks", "AI"],
        ["database", "indexing", "search"],
        ["vector search", "embeddings", "AI"],
        ["full text search", "indexing", "database"],
        ["python", "web development", "flask"],
        ["machine learning", "deep learning", "pytorch"],
        ["database", "SQL", "postgresql"],
        ["search engine", "elasticsearch", "indexing"],
        ["AI", "transformers", "NLP"]
      ][i],
      description: [
        "Python for data science projects",
        "Deep learning fundamentals",
        "Database indexing techniques",
        "Vector search implementations",
        "Full-text search guide",
        "Web development with Python",
        "Machine learning with PyTorch",
        "Database management systems",
        "Search engine optimization",
        "AI and NLP applications"
      ][i]
    })),
    { schema }
  );
  ```
</CodeGroup>

### Creating the Table and Adding Data

Create the table and populate it with the sample data:

<CodeGroup>
  ```python Python icon="python" theme={"theme":{"light":"vitesse-light","dark":"catppuccin-mocha"}}
  # Create table and add data
  table = db.create_table(table_name, schema=schema, mode="overwrite")
  table_data = pa.Table.from_pydict(data, schema=schema)
  table.add(table_data)
  ```

  ```typescript TypeScript icon="square-js" theme={"theme":{"light":"vitesse-light","dark":"catppuccin-mocha"}}
  // Create table
  const table = await db.createTable(tableName, data, { mode: "overwrite" });
  console.log(`Created table: ${tableName}`);
  ```
</CodeGroup>

### Building the Full-Text Search Index

Create an FTS index on the tags column to enable efficient text search:

<CodeGroup>
  ```python Python icon="python" theme={"theme":{"light":"vitesse-light","dark":"catppuccin-mocha"}}
  # Create FTS index
  table.create_fts_index("tags")
  wait_for_index(table, "tags_idx")
  ```

  ```typescript TypeScript icon="square-js" theme={"theme":{"light":"vitesse-light","dark":"catppuccin-mocha"}}
  // Create FTS index
  console.log("Creating FTS index on 'tags' column...");
  await table.createIndex("tags", {
    config: Index.fts()
  });

  // Wait for index
  const ftsIndexName = "tags_idx";
  await waitForIndex(table, ftsIndexName);
  ```
</CodeGroup>

### Performing Fuzzy Search

Search for terms with typos using fuzzy matching:

<CodeGroup>
  ```python Python icon="python" theme={"theme":{"light":"vitesse-light","dark":"catppuccin-mocha"}}
  # Search examples
  print("\nSearching for 'learning' in tags with a typo:")
  result = (
      table.search(MatchQuery("learnin", column="tags", fuzziness=1))
      .select(['id', 'tags', 'description'])
      .to_arrow()
  )
  ```

  ```typescript TypeScript icon="square-js"> theme={"theme":{"light":"vitesse-light","dark":"catppuccin-mocha"}}
  // Search examples
  console.log("\nSearching for 'learning' in tags with a typo:");
  const fuzzyResults = await table.query()
    .fullTextSearch(new MatchQuery("learnin", "tags", {
      fuzziness: 2,
    }))
    .select(["id", "tags", "description"])
    .toArray();
  console.log(fuzzyResults);
  ```
</CodeGroup>

### Performing Phrase Search

Search for exact phrases within the array fields:

<CodeGroup>
  ```python Python icon="python" theme={"theme":{"light":"vitesse-light","dark":"catppuccin-mocha"}}
  print("\nSearching for 'machine learning' in tags:")
  result = (
      table.search(PhraseQuery("machine learning", column="tags"))
      .select(['id', 'tags', 'description'])
      .to_arrow()
  )
  ```

  ```typescript TypeScript icon="square-js" theme={"theme":{"light":"vitesse-light","dark":"catppuccin-mocha"}}
  console.log("\nSearching for 'machine learning' in tags:");
  const phraseResults = await table.query()
    .fullTextSearch(new PhraseQuery("machine learning", "tags"))
    .select(["id", "tags", "description"])
    .toArray();
  console.log(phraseResults);
  ```
</CodeGroup>