> This page location: Math Functions > TRUNC
> Full Neon documentation index: https://neon.com/docs/llms.txt

# PostgreSQL TRUNC() Function

The PostgreSQL `TRUNC()` function returns a number truncated to a whole number or truncated to the specified decimal places.

## Syntax

The following illustrates the syntax of the PostgreSQL `TRUNC()` function:

```sql
TRUNC(number [, precision])
```

## Arguments

The `TRUNC()` function accepts two arguments.

**1) `number`**

The `number` argument is a numeric value to be truncated

**2) `precision`**

The `precision` argument is an integer that indicates the number of decimal places.

If the `precision` argument is a positive integer, the `TRUNC()` function truncates digits to the right of the decimal point.

In case the `precision` is a negative integer, the `TRUNC()` function replaces digits to the left of the decimal point.

The precision argument is optional. If you don't specify it, it defaults to zero (0). In other words, the `number` is truncated to a whole number.

## Return value

The PostgreSQL `TRUNC()` function returns the same [numeric data type](../postgresql-tutorial/postgresql-numeric) as the first argument if the second argument is not specified. Otherwise, the function returns a numeric value if both arguments are used.

## Examples

### 1) Truncate to a whole number example

The following example uses the `TRUNC()` function to truncate a number to an integer:

```sql
SELECT
    TRUNC(10.6);
```

The result is:

```
10
```

### 2) Truncate to the specified decimal place

The following statement truncates a number to 2 decimal places:

```sql
 SELECT
    TRUNC(
        1.234,
        2
    );
```

Here is the result:

```
1.23
```

### 3) Truncate numbers with a negative second argument example

Consider the following example:

```sql
SELECT
    TRUNC(150.45,-2)
```

The second argument is -2, therefore, the `TRUNC()` function replaced the digits to the left of the decimal point that resulting in:

```
100
```

### 4) Truncate numbers returned by a query

See the following `film`, `film_category`, and `category` tables in the [sample database](../postgresql-getting-started/postgresql-sample-database):

![film film\_category category tables](https://neon.com/postgresqltutorial/film-film_category-category-tables.png)The following statement calculates the average rental rate by film category:

```sql
SELECT
    NAME,
    TRUNC(AVG( rental_rate ),2)
FROM
    film
INNER JOIN film_category
        USING(film_id)
INNER JOIN category
        USING(category_id)
GROUP BY
    NAME
ORDER BY NAME;
```

In this example, we used the `TRUNC()` function to truncate the average rentals to two decimal places.

The following picture illustrates the result:

![PostgreSQL TRUNC example](https://neon.com/postgresqltutorial/PostgreSQL-TRUNC-example.png)
In this tutorial, you have learned how to use the PostgreSQL `TRUNC()` function to truncate numbers.

---

## Related docs (Math Functions)

- [ABS](https://neon.com/postgresql/postgresql-math-functions/postgresql-abs)
- [CBRT](https://neon.com/postgresql/postgresql-math-functions/postgresql-cbrt)
- [CEIL](https://neon.com/postgresql/postgresql-math-functions/postgresql-ceil)
- [DEGREES](https://neon.com/postgresql/postgresql-math-functions/postgresql-degrees)
- [DIV](https://neon.com/postgresql/postgresql-math-functions/postgresql-div)
- [EXP](https://neon.com/postgresql/postgresql-math-functions/postgresql-exp)
- [FACTORIAL](https://neon.com/postgresql/postgresql-math-functions/postgresql-factorial)
- [FLOOR](https://neon.com/postgresql/postgresql-math-functions/postgresql-floor)
- [GCD](https://neon.com/postgresql/postgresql-math-functions/postgresql-gcd)
- [LCM](https://neon.com/postgresql/postgresql-math-functions/postgresql-lcm)
- [LN](https://neon.com/postgresql/postgresql-math-functions/postgresql-ln)
- [LOG](https://neon.com/postgresql/postgresql-math-functions/postgresql-log)
- [MOD](https://neon.com/postgresql/postgresql-math-functions/postgresql-mod)
- [MIN_SCALE](https://neon.com/postgresql/postgresql-math-functions/postgresql-min_scale)
- [PI](https://neon.com/postgresql/postgresql-math-functions/postgresql-pi-function)
- [POWER](https://neon.com/postgresql/postgresql-math-functions/postgresql-power)
- [RADIANS](https://neon.com/postgresql/postgresql-math-functions/postgresql-radians)
- [RANDOM](https://neon.com/postgresql/postgresql-math-functions/postgresql-random)
- [ROUND](https://neon.com/postgresql/postgresql-math-functions/postgresql-round)
- [SCALE](https://neon.com/postgresql/postgresql-math-functions/postgresql-scale)
- [SIGN](https://neon.com/postgresql/postgresql-math-functions/postgresql-sign)
- [SQRT](https://neon.com/postgresql/postgresql-math-functions/postgresql-sqrt)
- [TRIM_SCALE](https://neon.com/postgresql/postgresql-math-functions/postgresql-trim_scale)
- [WIDTH_BUCKET](https://neon.com/postgresql/postgresql-math-functions/postgresql-width_bucket)