# DuckDB

## DuckDB

[DuckDB](https://duckdb.org/docs/) is a database that supports reading and querying Parquet files really fast. Begin by creating a connection to DuckDB, and then install and load the [`httpfs`](https://duckdb.org/docs/extensions/httpfs.html) extension to read and write remote files:

PythonJavaScriptCopied

```
import duckdb

url = "https://boincai.co/datasets/blog_authorship_corpus/resolve/refs%2Fconvert%2Fparquet/blog_authorship_corpus/train/0000.parquet"

con = duckdb.connect()
con.execute("INSTALL httpfs;")
con.execute("LOAD httpfs;")
```

Now you can write and execute your SQL query on the Parquet file:

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```
con.sql(f"SELECT horoscope, count(*), AVG(LENGTH(text)) AS avg_blog_length FROM '{url}' GROUP BY horoscope ORDER BY avg_blog_length DESC LIMIT(5)")
┌───────────┬──────────────┬────────────────────┐
│ horoscope │ count_star() │  avg_blog_length   │
│  varchar  │    int64     │       double       │
├───────────┼──────────────┼────────────────────┤
│ Aquarius  │        34062 │  1129.218836239798 │
│ Cancer    │        41509 │  1098.366812016671 │
│ Capricorn │        33961 │ 1073.2002002296751 │
│ Libra     │        40302 │ 1072.0718326633914 │
│ Leo       │        40587 │ 1064.0536871412028 │
└───────────┴──────────────┴────────────────────┘
```

To query multiple files - for example, if the dataset is sharded:

PythonJavaScriptCopied

```
con.sql(f"SELECT horoscope, count(*), AVG(LENGTH(text)) AS avg_blog_length FROM read_parquet({urls[:2]}) GROUP BY horoscope ORDER BY avg_blog_length DESC LIMIT(5)")
┌─────────────┬──────────────┬────────────────────┐
│  horoscope  │ count_star() │  avg_blog_length   │
│   varchar   │    int64     │       double       │
├─────────────┼──────────────┼────────────────────┤
│ Aquarius    │        49568 │ 1125.8306770497095 │
│ Cancer      │        63512 │   1097.95608703867 │
│ Libra       │        60304 │ 1060.6110539931017 │
│ Capricorn   │        49402 │ 1059.5552609206104 │
│ Sagittarius │        50431 │ 1057.4589835616982 │
└─────────────┴──────────────┴────────────────────┘
```

[DuckDB-Wasm](https://duckdb.org/docs/api/wasm), a package powered by [WebAssembly](https://webassembly.org/), is also available for running DuckDB in any browser. This could be useful, for instance, if you want to create a web app to query Parquet files from the browser!


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# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://boinc-ai.gitbook.io/datasets-server/guides/query-datasets-from-datasets-server/duckdb.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.