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

> Reference for Iceberg functions

# Iceberg functions

## Iceberg functions

Iceberg functions provide utilities for working with [Apache Iceberg](https://iceberg.apache.org/) tables. These functions include table-valued functions for reading Iceberg data and partition transform functions that implement the [Iceberg partition transforms specification](https://iceberg.apache.org/spec/#partition-transforms).

### Reading Iceberg data

Use the [`READ_ICEBERG`](/reference-sql/functions-reference/iceberg/read_iceberg) table-valued function to query data from Iceberg tables stored in file-based catalogs or REST catalogs.

```sql theme={"theme":{"light":"github-light","dark":"github-dark"}}
SELECT * 
FROM READ_ICEBERG(
  LOCATION => 'my_iceberg_location',
  MAX_STALENESS => INTERVAL '30 seconds'
) 
LIMIT 5;
```

### Partition transform functions

Iceberg partition transform functions compute partition values according to the [Iceberg specification](https://iceberg.apache.org/spec/#partition-transforms). These functions can be used in the `PARTITION BY` clause of [`CREATE ICEBERG TABLE`](/reference-sql/commands/data-definition/create-iceberg-table-as-select) commands.

```sql theme={"theme":{"light":"github-light","dark":"github-dark"}}
SELECT 
  iceberg_year('2025-12-15'::DATE) AS year_partition,
  iceberg_month('2025-12-15'::DATE) AS month_partition,
  iceberg_day('2025-12-15'::DATE) AS day_partition;
```

**Returns:**

| year\_partition | month\_partition | day\_partition |
| :-------------- | :--------------- | :------------- |
| 55              | 671              | 20437          |

### Available functions

**Table-valued functions:**

* [`READ_ICEBERG`](/reference-sql/functions-reference/iceberg/read_iceberg) - Read data from Iceberg tables

**Partition transform functions:**

* [`ICEBERG_YEAR`](/reference-sql/functions-reference/iceberg/partitioning/iceberg_year) - Extract year as years from 1970
* [`ICEBERG_MONTH`](/reference-sql/functions-reference/iceberg/partitioning/iceberg_month) - Extract month as months from 1970-01-01
* [`ICEBERG_DAY`](/reference-sql/functions-reference/iceberg/partitioning/iceberg_day) - Extract day as days from 1970-01-01
* [`ICEBERG_HOUR`](/reference-sql/functions-reference/iceberg/partitioning/iceberg_hour) - Extract hour as hours from 1970-01-01 00:00:00
* [`ICEBERG_BUCKET`](/reference-sql/functions-reference/iceberg/partitioning/iceberg_bucket) - Hash value into a bucket
* [`ICEBERG_TRUNCATE`](/reference-sql/functions-reference/iceberg/partitioning/iceberg_truncate) - Truncate value to a width