# trunc

[Read this page in HTML](https://www.scopedb.io/docs/reference/functions/numeric/trunc)

Truncates the fractional part of a number toward zero.

## Syntax

```scopeql
trunc(<expr>)
```

## Arguments

| Argument | Type    | Description  |
| -------- | ------- | ------------ |
| `<expr>` | `float` | Input value. |

## Returns

Returns `float`. Returns NULL if the input is NULL.

## Usage notes

For an `int` or `uint` column, cast the value to `float` before calling this function.

## Examples

Discard fractional units from signed measurements. Compare truncation with floor when corrections can be negative.

```scopeql
VALUES ('received', 12.8), ('returned', -12.8)
SELECT $0 AS movement, $1 AS measured_units
SELECT
    movement,
    measured_units,
    trunc(measured_units) AS truncated_units,
    floor(measured_units) AS floor_units
```

```text
+----------+----------------+-----------------+-------------+
| movement | measured_units | truncated_units | floor_units |
+----------+----------------+-----------------+-------------+
| received | 12.8           | 12.0            | 12.0        |
| returned | -12.8          | -12.0           | -13.0       |
+----------+----------------+-----------------+-------------+
```

Truncation moves toward zero; floor moves toward negative infinity. They differ for the returned quantity.