---
title: 'PostgreSQL ROUND() Function'
page_title: 'PostgreSQL ROUND() Function'
page_description: 'Show you how to use the PostgreSQL ROUND() function to round a number to its nearest integer or a number of specified decimal places.'
prev_url: 'https://www.postgresqltutorial.com/postgresql-math-functions/postgresql-round/'
ogImage: '/postgresqltutorial/customer-and-payment-tables.png'
updatedOn: '2024-02-16T14:25:02+00:00'
enableTableOfContents: true
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  title: 'PostgreSQL RANDOM() Function'
  slug: 'postgresql-math-functions/postgresql-random'
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  title: 'PostgreSQL SQRT() Function'
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---

The PostgreSQL `ROUND()` function rounds a numeric value to its nearest [integer](../postgresql-tutorial/postgresql-integer) or a number with the number of decimal places.

## Syntax

The following illustrates the syntax of the `ROUND()` function:

```css
ROUND (source [ , n ] )
```

## Arguments

The `ROUND()` function accepts 2 arguments:

1\) source

The `source` argument is a number or a numeric expression that is to be rounded.

2\) n

The `n` argument is an integer that determines the number of decimal places after rounding.

The n argument is optional. If you omit the n argument, its default value is 0\.

## Return value

The `ROUND()` function returns a result whose type is the same as the input if you omit the second argument.

If you use both arguments, the `ROUND()` function returns a numeric value.

## Examples

### 1\) Basic ROUND() function example

The following example shows how to round a decimal using the `ROUND()` function:

```css
SELECT
    ROUND( 10.4 );
```

Because the nearest integer of 10\.4 is 10, the function returns 10 as expected:

```css
10
```

The following example rounds 10\.5:

```
SELECT
    ROUND( 10.5 );
```

Output:

```css
11
```

### 2\) Round to 2 decimal places examples

The following example uses the `ROUND()` function to round a number to the one with 2 decimal places:

```
SELECT
    ROUND( 10.812, 2 );
```

Result:

```css
10.81
```

And another example of rounding a decimal to 2 decimal places:

```css
SELECT
    ROUND( 10.817, 2 );
```

Result:

```css
10.82
```

You can change the second argument to round a number to specific decimal places.

### 3\) Rounding data from table examples

We will use the following `payment` and `customer` tables in the [sample database](../postgresql-getting-started/postgresql-sample-database) for the demonstration.

![customer and payment tables](/postgresqltutorial/customer-and-payment-tables.png)The following statement retrieves the average rental fee that each customer has paid.

```php
SELECT
    first_name,
    last_name,
    ROUND( AVG( amount ), 2 ) avg_rental
FROM
    payment
INNER JOIN customer
        USING(customer_id)
GROUP BY
    customer_id
ORDER BY
    avg_rental DESC;
```

In this statement, we use the `ROUND()` function to round the average rental fee to 2 decimal places.

Output:

```
first_name  |  last_name   | avg_rental
-------------+--------------+------------
 Brittany    | Riley        |       5.62
 Kevin       | Schuler      |       5.52
 Ruth        | Martinez     |       5.49
 Linda       | Williams     |       5.45
 Paul        | Trout        |       5.39
 Daniel      | Cabral       |       5.30
...
```

The following statement calculates the average number of rentals per customer:

```
WITH rental(customer_id,rent) AS
(
    SELECT
        customer_id,
        COUNT( rental_id )
    FROM
        payment
    GROUP BY
        customer_id
)
SELECT
    ROUND(AVG(rent))
FROM
    rental;
```

Output:

```
 round
-------
    24
(1 row)
```

In this example, we used the `ROUND()` function to round the result to an integer.

## Summary

- Use the PostgreSQL `ROUND()` function to round a number to its nearest integer or a number of specified decimal places.