# MV_FIRST

Converts a multivalued expression into a single-valued column containing the first value. This is particularly useful when working with functions like `SPLIT` that produce multivalued columns in a known order.

## Syntax

`MV_FIRST(field)`

### Parameters

#### `field`

A multivalued expression.

## Examples

Extracting the first value from a multivalued column

```esql
ROW a="foo;bar;baz"
| EVAL first_a = MV_FIRST(SPLIT(a, ";"))
```

This example splits the string `a` into multiple values using the `SPLIT` function and extracts the first value, resulting in `first_a = "foo"`.

## Notes

- The order in which multivalued fields are read from underlying storage is not guaranteed. While it is often ascending, this behavior should not be relied upon.
- If you need the minimum value, use `MV_MIN` instead of `MV_FIRST`. The `MV_MIN` function is optimized for sorted values and offers no performance disadvantage compared to `MV_FIRST`.
