> ## Documentation Index
> Fetch the complete documentation index at: https://docs.e6data.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Other

*The Ingest Engine scalar functions are based on* [*Apache DataFusion*](https://arrow.apache.org/datafusion/) *and these docs are derived from the DataFusion function reference.*

## `arrow_cast`

Casts a value to a specific Arrow data type:

```
arrow_cast(expression, datatype)
```

**Arguments**

* **expression**: Expression to cast. Can be a constant, column, or function, and any combination of arithmetic or string operators.
* **datatype**: [Arrow data type](https://docs.rs/arrow/latest/arrow/datatypes/enum.DataType.html) name to cast to, as a string. The format is the same as that returned by [`arrow_typeof`](#arrow_typeof).

**Example**

```sql theme={"theme":{"light":"github-light","dark":"github-dark"}}
> select arrow_cast(-5, 'Int8') as a,
  arrow_cast('foo', 'Dictionary(Int32, Utf8)') as b,
  arrow_cast('bar', 'LargeUtf8') as c,
  arrow_cast('2023-01-02T12:53:02', 'Timestamp(Microsecond, Some("+08:00"))') as d
  ;
+----+-----+-----+---------------------------+
| a  | b   | c   | d                         |
+----+-----+-----+---------------------------+
| -5 | foo | bar | 2023-01-02T12:53:02+08:00 |
+----+-----+-----+---------------------------+
1 row in set. Query took 0.001 seconds.
```

## `arrow_typeof`

Returns the name of the underlying [Arrow data type](https://docs.rs/arrow/latest/arrow/datatypes/enum.DataType.html) of the expression:

```
arrow_typeof(expression)
```

**Arguments**

* **expression**: Expression to evaluate. Can be a constant, column, or function, and any combination of arithmetic or string operators.

**Example**

```sql theme={"theme":{"light":"github-light","dark":"github-dark"}}
> select arrow_typeof('foo'), arrow_typeof(1);
+---------------------------+------------------------+
| arrow_typeof(Utf8("foo")) | arrow_typeof(Int64(1)) |
+---------------------------+------------------------+
| Utf8                      | Int64                  |
+---------------------------+------------------------+
1 row in set. Query took 0.001 seconds.
```


This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.