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

> Provides a table-like interface to select/insert files in Azure Blob Storage. Similar to the s3 function.

# azureBlobStorage

export const CloudNotSupportedBadge = () => {
  return <div className="cloudNotSupportedBadge">
            <div className="cloudNotSupportedIcon">
            <svg width="16" height="16" viewBox="0 0 16 16" fill="none" xmlns="http://www.w3.org/2000/svg">
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                <path strokeWidth="1.5" d="M2.66699 14L12.0003 4.66663" stroke="currentColor" strokeLinecap="round" strokeLinejoin="round" />
            </svg>

        </div>
            Not supported in ClickHouse Cloud
        </div>;
};

export const ExperimentalBadge = () => {
  return <div className="experimentalBadge">
            <div className="experimentalIcon">
            <svg width="16" height="16" viewBox="0 0 16 16" fill="none" xmlns="http://www.w3.org/2000/svg">
                <path strokeWidth="1.25" d="M5.5 2H10.5" stroke="currentColor" strokeLinecap="round" strokeLinejoin="round" />
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            </svg>
        </div>
            Experimental feature. <u><a href="/docs/beta-and-experimental-features#experimental-features">Learn more.</a></u>
        </div>;
};

# azureBlobStorage Table Function

Provides a table-like interface to select/insert files in [Azure Blob Storage](https://azure.microsoft.com/en-us/products/storage/blobs). This table function is similar to the [s3 function](/reference/functions/table-functions/s3).

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

<Tabs>
  <Tab title="Connection string">
    Credentials are embedded in the connection string, so no separate `account_name`/`account_key` is needed:

    ```sql theme={null}
    azureBlobStorage(connection_string, container_name, blobpath [, format, compression, structure])
    ```
  </Tab>

  <Tab title="Storage account URL">
    Requires `account_name` and `account_key` as separate arguments:

    ```sql theme={null}
    azureBlobStorage(storage_account_url, container_name, blobpath, account_name, account_key [, format, compression, structure])
    ```
  </Tab>

  <Tab title="Named collection">
    See [Named Collections](#named-collections) below for the full list of supported keys:

    ```sql theme={null}
    azureBlobStorage(named_collection[, option=value [,..]])
    ```
  </Tab>
</Tabs>

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

| Argument                         | Description                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |
| -------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `connection_string`              | A connection string that includes embedded credentials (account name + account key or SAS token). When using this form, `account_name` and `account_key` should **not** be passed separately. See [Configure a connection string](https://learn.microsoft.com/en-us/azure/storage/common/storage-configure-connection-string?toc=%2Fazure%2Fstorage%2Fblobs%2Ftoc.json\&bc=%2Fazure%2Fstorage%2Fblobs%2Fbreadcrumb%2Ftoc.json#configure-a-connection-string-for-an-azure-storage-account).          |
| `storage_account_url`            | The storage account endpoint URL, e.g. `https://myaccount.blob.core.windows.net/`. When using this form, you **must** also pass `account_name` and `account_key`.                                                                                                                                                                                                                                                                                                                                   |
| `container_name`                 | Container name.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     |
| `blobpath`                       | File path. Supports the following wildcards in read-only mode: `*`, `**`, `?`, `{abc,def}` and `{N..M}` where `N`, `M` — numbers, `'abc'`, `'def'` — strings.                                                                                                                                                                                                                                                                                                                                       |
| `account_name`                   | Storage account name. **Required** when using `storage_account_url` without SAS; must **not** be passed when using `connection_string`.                                                                                                                                                                                                                                                                                                                                                             |
| `account_key`                    | Storage account key. **Required** when using `storage_account_url` without SAS; must **not** be passed when using `connection_string`.                                                                                                                                                                                                                                                                                                                                                              |
| `format`                         | The [format](/reference/formats/index) of the file.                                                                                                                                                                                                                                                                                                                                                                                                                                                 |
| `compression`                    | Supported values: `none`, `gzip/gz`, `brotli/br`, `xz/LZMA`, `zstd/zst`. By default, it will autodetect compression by file extension (same as setting to `auto`).                                                                                                                                                                                                                                                                                                                                  |
| `structure`                      | Structure of the table. Format `'column1_name column1_type, column2_name column2_type, ...'`.                                                                                                                                                                                                                                                                                                                                                                                                       |
| `partition_strategy`             | Optional. Supported values: `WILDCARD` or `HIVE`. `WILDCARD` requires a `{_partition_id}` in the path, which is replaced with the partition key. `HIVE` does not allow wildcards, assumes the path is the table root, and generates Hive-style partitioned directories with Snowflake IDs as filenames and the file format as the extension. Defaults to the `file_like_engine_default_partition_strategy` setting (`WILDCARD` under `compatibility` settings older than `26.6`, `HIVE` otherwise). |
| `partition_columns_in_data_file` | Optional. Only used with `HIVE` partition strategy. Tells ClickHouse whether to expect partition columns to be written in the data file. Defaults `false`.                                                                                                                                                                                                                                                                                                                                          |
| `extra_credentials`              | Use `client_id` and `tenant_id` for authentication. If extra\_credentials are provided, they are given priority over `account_name` and `account_key`.                                                                                                                                                                                                                                                                                                                                              |

<h2 id="named-collections">
  Named Collections
</h2>

Arguments can also be passed using [named collections](/concepts/features/configuration/server-config/named-collections). In this case the following keys are supported:

| Key                   | Required | Description                                                                                                          |
| --------------------- | -------- | -------------------------------------------------------------------------------------------------------------------- |
| `container`           | Yes      | Container name. Corresponds to the positional argument `container_name`.                                             |
| `blob_path`           | Yes      | File path (with optional wildcards). Corresponds to the positional argument `blobpath`.                              |
| `connection_string`   | No\*     | Connection string with embedded credentials. \*Either `connection_string` or `storage_account_url` must be provided. |
| `storage_account_url` | No\*     | Storage account endpoint URL. \*Either `connection_string` or `storage_account_url` must be provided.                |
| `account_name`        | No       | Required when using `storage_account_url`                                                                            |
| `account_key`         | No       | Required when using `storage_account_url`                                                                            |
| `format`              | No       | File format.                                                                                                         |
| `compression`         | No       | Compression type.                                                                                                    |
| `structure`           | No       | Table structure.                                                                                                     |
| `client_id`           | No       | Client ID for authentication.                                                                                        |
| `tenant_id`           | No       | Tenant ID for authentication.                                                                                        |

<Note>
  Named collection key names differ from positional function argument names: `container` (not `container_name`) and `blob_path` (not `blobpath`).
</Note>

**Example:**

```sql theme={null}
CREATE NAMED COLLECTION azure_my_data AS
    storage_account_url = 'https://myaccount.blob.core.windows.net/',
    container = 'mycontainer',
    blob_path = 'data/*.parquet',
    account_name = 'myaccount',
    account_key = 'mykey...==',
    format = 'Parquet';

SELECT *
FROM azureBlobStorage(azure_my_data)
LIMIT 5;
```

You can also override named collection values at query time:

```sql theme={null}
SELECT *
FROM azureBlobStorage(azure_my_data, blob_path = 'other_data/*.csv', format = 'CSVWithNames')
LIMIT 5;
```

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

A table with the specified structure for reading or writing data in the specified file.

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

<h3 id="reading-with-storage-account-url">
  Reading with `storage_account_url` form
</h3>

```sql theme={null}
SELECT *
FROM azureBlobStorage(
    'https://myaccount.blob.core.windows.net/',
    'mycontainer',
    'data/*.parquet',
    'myaccount',
    'mykey...==',
    'Parquet'
)
LIMIT 5;
```

<h3 id="reading-with-connection-string">
  Reading with `connection_string` form
</h3>

```sql theme={null}
SELECT *
FROM azureBlobStorage(
    'DefaultEndpointsProtocol=https;AccountName=myaccount;AccountKey=mykey...==;EndPointSuffix=core.windows.net',
    'mycontainer',
    'data/*.csv',
    'CSVWithNames'
)
LIMIT 5;
```

<h3 id="writing-with-partitions">
  Writing with partitions
</h3>

```sql theme={null}
INSERT INTO TABLE FUNCTION azureBlobStorage(
    'DefaultEndpointsProtocol=https;AccountName=myaccount;AccountKey=mykey...==;EndPointSuffix=core.windows.net',
    'mycontainer',
    'test_{_partition_id}.csv',
    'CSV',
    'auto',
    'column1 UInt32, column2 UInt32, column3 UInt32'
) PARTITION BY column3
VALUES (1, 2, 3), (3, 2, 1), (78, 43, 3);
```

Then read back a specific partition:

```sql theme={null}
SELECT *
FROM azureBlobStorage(
    'DefaultEndpointsProtocol=https;AccountName=myaccount;AccountKey=mykey...==;EndPointSuffix=core.windows.net',
    'mycontainer',
    'test_1.csv',
    'CSV',
    'auto',
    'column1 UInt32, column2 UInt32, column3 UInt32'
);
```

```response theme={null}
┌─column1─┬─column2─┬─column3─┐
│       3 │       2 │       1 │
└─────────┴─────────┴─────────┘
```

<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`.

<h2 id="partitioned-write">
  Partitioned Write
</h2>

<h3 id="partition-strategy">
  Partition Strategy
</h3>

Supported for INSERT queries only.

`WILDCARD`: Replaces the `{_partition_id}` wildcard in the file path with the actual partition key. Selected by default only under `compatibility` settings older than `26.6`; otherwise the default is `HIVE` (see the `file_like_engine_default_partition_strategy` setting).

`HIVE` implements hive style partitioning for reads & writes. It generates files using the following format: `<prefix>/<key1=val1/key2=val2...>/<snowflakeid>.<toLower(file_format)>`.

**Example of `HIVE` partition strategy**

```sql theme={null}
INSERT INTO TABLE FUNCTION azureBlobStorage(
    azure_conf2,
    storage_account_url = 'https://myaccount.blob.core.windows.net/',
    container = 'cont',
    blob_path = 'azure_table_root',
    format = 'CSVWithNames',
    compression = 'auto',
    structure = 'year UInt16, country String, id Int32',
    partition_strategy = 'hive'
) PARTITION BY (year, country)
VALUES (2020, 'Russia', 1), (2021, 'Brazil', 2);
```

```result theme={null}
SELECT _path, * FROM azureBlobStorage(
    azure_conf2,
    storage_account_url = 'https://myaccount.blob.core.windows.net/',
    container = 'cont',
    blob_path = 'azure_table_root/**.csvwithnames'
)

   ┌─_path───────────────────────────────────────────────────────────────────────────┬─id─┬─year─┬─country─┐
1. │ cont/azure_table_root/year=2021/country=Brazil/7351307847391293440.csvwithnames │  2 │ 2021 │ Brazil  │
2. │ cont/azure_table_root/year=2020/country=Russia/7351307847378710528.csvwithnames │  1 │ 2020 │ Russia  │
   └─────────────────────────────────────────────────────────────────────────────────┴────┴──────┴─────────┘
```

<h2 id="hive-style-partitioning">
  use\_hive\_partitioning setting
</h2>

This is a hint for ClickHouse to parse hive style partitioned files upon reading time. It has no effect on writing. For symmetrical reads and writes, use the `partition_strategy` argument.

When setting `use_hive_partitioning` is set to 1, ClickHouse will detect Hive-style partitioning in the path (`/name=value/`) and will allow to use partition columns as virtual columns in the query. These virtual columns will have the same names as in the partitioned path.

**Example**

Use virtual column, created with Hive-style partitioning

```sql theme={null}
SELECT * FROM azureBlobStorage(config, storage_account_url='...', container='...', blob_path='http://data/path/date=*/country=*/code=*/*.parquet') WHERE date > '2020-01-01' AND country = 'Netherlands' AND code = 42;
```

<h2 id="using-shared-access-signatures-sas-sas-tokens">
  Using Shared Access Signatures (SAS)
</h2>

A Shared Access Signature (SAS) is a URI that grants restricted access to an Azure Storage container or file. Use it to provide time-limited access to storage account resources without sharing your storage account key. More details [here](https://learn.microsoft.com/en-us/rest/api/storageservices/delegate-access-with-shared-access-signature).

The `azureBlobStorage` function supports Shared Access Signatures (SAS).

A [Blob SAS token](https://learn.microsoft.com/en-us/azure/ai-services/translator/document-translation/how-to-guides/create-sas-tokens?tabs=Containers) contains all the information needed to authenticate the request, including the target blob, permissions, and validity period. To construct a blob URL, append the SAS token to the blob service endpoint. For example, if the endpoint is `https://clickhousedocstest.blob.core.windows.net/`, the request becomes:

```sql theme={null}
SELECT count()
FROM azureBlobStorage('BlobEndpoint=https://clickhousedocstest.blob.core.windows.net/;SharedAccessSignature=sp=r&st=2025-01-29T14:58:11Z&se=2025-01-29T22:58:11Z&spr=https&sv=2022-11-02&sr=c&sig=Ac2U0xl4tm%2Fp7m55IilWl1yHwk%2FJG0Uk6rMVuOiD0eE%3D', 'exampledatasets', 'example.csv')

┌─count()─┐
│      10 │
└─────────┘

1 row in set. Elapsed: 0.425 sec.
```

Alternatively, users can use the generated [Blob SAS URL](https://learn.microsoft.com/en-us/azure/ai-services/translator/document-translation/how-to-guides/create-sas-tokens?tabs=Containers):

```sql theme={null}
SELECT count()
FROM azureBlobStorage('https://clickhousedocstest.blob.core.windows.net/?sp=r&st=2025-01-29T14:58:11Z&se=2025-01-29T22:58:11Z&spr=https&sv=2022-11-02&sr=c&sig=Ac2U0xl4tm%2Fp7m55IilWl1yHwk%2FJG0Uk6rMVuOiD0eE%3D', 'exampledatasets', 'example.csv')

┌─count()─┐
│      10 │
└─────────┘

1 row in set. Elapsed: 0.153 sec.
```

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

* [AzureBlobStorage Table Engine](/reference/engines/table-engines/integrations/azureBlobStorage)