To load a CSV file directly over HTTP(S), the httpfs extension is required. This can be installed using the INSTALL SQL command. This only needs to be run once.

INSTALL httpfs;

To load the httpfs extension for usage, use the LOAD SQL command:

LOAD httpfs;

After the httpfs extension is set up, CSV files can be read over http(s) the same way as a local file, using read_csv:

SELECT * FROM read_csv('https://⟨domain⟩/path/to/file.csv');

Moreover, the read_csv function itself can also be omitted thanks to DuckDB's replacement scan mechanism:

SELECT * FROM 'https://⟨domain⟩/path/to/file.csv';

Example

The following query reads an openly licensed (CC BY 4.0) real-world CSV directly over HTTP and aggregates it, with no local download step:

SELECT
    area,
    round(avg(sunbed_price), 0) AS avg_sunbed_price_eur,
    count(*) AS clubs
FROM 'http://blobs.duckdb.org/data/beach-clubs.csv'
WHERE sunbed_price IS NOT NULL
GROUP BY area
ORDER BY avg_sunbed_price_eur DESC;

┌────────────────────────────┬──────────────────────┬───────┐
│            area            │ avg_sunbed_price_eur │ clubs │
│          varchar           │        double        │ int64 │
├────────────────────────────┼──────────────────────┼───────┤
│ Marbella centre (El Cable) │                120.0 │     1 │
│ Puerto Banús               │                103.0 │     4 │
│ Golden Mile                │                 70.0 │     1 │
│ El Rosario (Marbella East) │                 30.0 │     1 │
│ Elviria (Marbella East)    │                 30.0 │     1 │
│ Marbella centre            │                 20.0 │     1 │
│ Casablanca (Golden Mile)   │                 15.0 │     1 │
└────────────────────────────┴──────────────────────┴───────┘

Because read_csv streams the file rather than materializing it first, this works the same way for CSVs far larger than fit in memory, and pairs naturally with read_csv's usual options (columns, types, delim, etc.) for files that need explicit schema hints.