datafusion-extra-functions 0.5.3

Extra Functions for DataFusion
Documentation 
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# datafusion-extra-functions

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Extra aggregate functions for [Apache DataFusion](https://datafusion.apache.org/). This is not an official Apache Software Foundation release.

Version `0.5.3` supports DataFusion `55.0` and Rust edition 2024.

## Installation

```sh
cargo add datafusion-extra-functions
```

Register all functions with your session context:

```rust
datafusion_extra_functions::register_all_extra_functions(&mut ctx)?;
```

## Available functions

| Function | Description |
| --- | --- |
| `mode(expression)` | Returns most frequent value. |
| `max_by(value, key)` | Returns value at maximum key. |
| `min_by(value, key)` | Returns value at minimum key. |
| `skewness(expression)` | Computes skewness. |
| `kurtosis_pop(expression)` | Computes population excess kurtosis. |
| `kurtosis(expression)` | Computes sample excess kurtosis. |

```sql
SELECT mode(city) FROM visits;
SELECT max_by(user_id, score) FROM results;
SELECT min_by(user_id, score) FROM results;
SELECT skewness(measurement) FROM readings;
SELECT kurtosis_pop(measurement) FROM readings;
SELECT kurtosis(measurement) FROM readings;
```

## Testing

```sh
cargo test
```