> ## Documentation Index
> Fetch the complete documentation index at: https://private-7c7dfe99-mintlify-8a08bda2.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

> Provides a read-only table-like interface to the Delta Lake tables in Amazon S3.

# deltaLake

Provides a table-like interface to [Delta Lake](https://github.com/delta-io/delta) tables in Amazon S3, Azure Blob Storage, or a locally mounted file system, supporting both reads and writes (from v25.10)

<h2 id="syntax">
  Syntax
</h2>

`deltaLake` is an alias of `deltaLakeS3` which is supported for compatibility.

```sql theme={null}
deltaLake(url [,aws_access_key_id, aws_secret_access_key] [,format] [,structure] [,compression] [,extra_credentials])

deltaLakeS3(url [,aws_access_key_id, aws_secret_access_key] [,format] [,structure] [,compression] [,extra_credentials])

deltaLakeAzure(connection_string|storage_account_url, container_name, blobpath, [,account_name], [,account_key] [,format] [,compression_method])

deltaLakeLocal(path, [,format])
```

<h2 id="arguments">
  Arguments
</h2>

The arguments for this table function are the same as for the `s3`, `azureBlobStorage`, `HDFS` and `file` table functions respectively.
The `format` argument stands for the format of data files in the Delta lake table.

An optional `extra_credentials` parameter can be used to pass a `role_arn` for role-based access in ClickHouse Cloud. See [Secure S3](/products/cloud/guides/data-sources/accessing-s3-data-securely) for configuration steps.

<h2 id="returned_value">
  Returned value
</h2>

Returns a table with the specified structure for reading or writing data from/to the specified Delta Lake table.

<h2 id="examples">
  Examples
</h2>

<h3 id="reading-data">
  Reading data
</h3>

Consider a table in S3 storage at `https://clickhouse-public-datasets.s3.amazonaws.com/delta_lake/hits/`.
To read data from the table in ClickHouse, run:

```sql title="Query" theme={null}
SELECT
    URL,
    UserAgent
FROM deltaLake('https://clickhouse-public-datasets.s3.amazonaws.com/delta_lake/hits/')
WHERE URL IS NOT NULL
LIMIT 2
```

```response title="Response" theme={null}
┌─URL───────────────────────────────────────────────────────────────────┬─UserAgent─┐
│ http://auto.ria.ua/search/index.kz/jobinmoscow/detail/55089/hasimages │         1 │
│ http://auto.ria.ua/search/index.kz/jobinmoscow.ru/gosushi             │         1 │
└───────────────────────────────────────────────────────────────────────┴───────────┘
```

<h3 id="inserting-data">
  Inserting data
</h3>

Consider a table in S3 storage at `s3://ch-docs-s3-bucket/people_10k/`.
To insert data into the table, first enable the experimental feature:

```sql title="Query" theme={null}
SET allow_experimental_delta_lake_writes=1
```

Then write:

```sql title="Query" theme={null}
INSERT INTO TABLE FUNCTION deltaLake('s3://ch-docs-s3-bucket/people_10k/', '<access_key>', '<secret>') VALUES (10001, 'John', 'Smith', 'Male', 30)
```

```response title="Response" theme={null}
Query id: 09069b47-89fa-4660-9e42-3d8b1dde9b17

Ok.

1 row in set. Elapsed: 3.426 sec.
```

You can confirm the insert worked by reading the table again:

```sql title="Query" theme={null}
SELECT *
FROM deltaLake('s3://ch-docs-s3-bucket/people_10k/', '<access_key>', '<secret>')
WHERE (firstname = 'John') AND (lastname = 'Smith')
```

```response title="Response" theme={null}
Query id: 65032944-bed6-4d45-86b3-a71205a2b659

   ┌────id─┬─firstname─┬─lastname─┬─gender─┬─age─┐
1. │ 10001 │ John      │ Smith    │ Male   │  30 │
   └───────┴───────────┴──────────┴────────┴─────┘
```

<h2 id="virtual-columns">
  Virtual Columns
</h2>

* `_path` — Path to the file. Type: `LowCardinality(String)`.
* `_file` — Name of the file. Type: `LowCardinality(String)`.
* `_size` — Size of the file in bytes. Type: `Nullable(UInt64)`. If the file size is unknown, the value is `NULL`.
* `_time` — Last modified time of the file. Type: `Nullable(DateTime)`. If the time is unknown, the value is `NULL`.
* `_etag` — The etag of the file. Type: `LowCardinality(String)`. If the etag is unknown, the value is `NULL`.

<h2 id="related">
  Related
</h2>

* [DeltaLake engine](/reference/engines/table-engines/integrations/deltalake)
* [DeltaLake cluster table function](/reference/functions/table-functions/deltalakeCluster)