---
title: 'PostgreSQL NTH_VALUE Function'
page_title: 'PostgreSQL NTH_VALUE() Function By Practical Examples'
page_description: 'In this tutorial, you will learn how to use the PostgreSQL NTH_VALUE() function to get a value from the nth row in a result set.'
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updatedOn: '2020-04-11T10:53:01+00:00'
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---

**Summary**: in this tutorial, you will learn how to use the PostgreSQL `NTH_VALUE()` function to get a value from the nth row in a result set.

## Introduction to PostgreSQL NTH_VALUE() function

The `NTH_VALUE()` function returns a value from the nth row in an ordered partition of a result set.

Here is the syntax of the `NTH_VALUE()` function:

```sql
NTH_VALUE(expression, offset)
OVER (
    [PARTITION BY partition_expression]
    [ ORDER BY sort_expression [ASC | DESC]
    frame_clause ]
)

```

Let’s examine the syntax of the `NTH_VALUE()` function in detail.

### expression

The `expression` is the target column or expression on which the `NTH_VALUE()` function operates.

### offset

The `offset` is a positive integer (greater than zero) that determines the row number relative to the first row in the window against which the expression evaluates.

### PARTITION BY partition_expression

The `PARTITION BY` clause distributes rows of the result set into partitions to which the `NTH_VALUE()` function applies.

### ORDER BY sort_expression

The `ORDER BY` clause sorts rows in each partition to which the function is applied.

### frame clause

The `frame_clause` defines the subset (or the frame) of the current partition.

## PostgreSQL NTH_VALUE() function examples

We will use the `products` table created in the window functions tutorial for the demonstration.

![](/postgresqltutorial/products-table-sample-data.png)

### 1\) Using PostgreSQL NTH_VALUE() function over the result set example

This example uses the `NTH_VALUE()` function to return all products together with the second most expensive product:

```sql
SELECT
    product_id,
    product_name,
    price,
    NTH_VALUE(product_name, 2)
    OVER(
        ORDER BY price DESC
        RANGE BETWEEN
            UNBOUNDED PRECEDING AND
            UNBOUNDED FOLLOWING
    )
FROM
    products;

```

Here is the output:

![PostgreSQL NTH_VALUE function over a result set example](/postgresqltutorial/PostgreSQL-NTH_VALUE-function-over-a-result-set-example.png)
In this example:

- The `ORDER BY` clause sorted all products by prices from high to low
- The frame clause defined the frame start at the beginning row and end at the ending row of the result set.
- The `NTH_VALUE()` function return value in the product_name column of the second row of the result set after sorting and framing.

### 2\) Using PostgreSQL NTH_VALUE() function over a partition example

This example uses the `NTH_VALUE()` function to return all products with the second most expensive product for each product group:

```sql
SELECT
    product_id,
    product_name,
    price,
    group_id,
    NTH_VALUE(product_name, 2)
    OVER(
        PARTITION BY group_id
        ORDER BY price DESC
        RANGE BETWEEN
            UNBOUNDED PRECEDING AND
            UNBOUNDED FOLLOWING
    )
FROM
    products;

```

The following picture illustrates the output:

![PostgreSQL NTH_VALUE function over a partition example](/postgresqltutorial/PostgreSQL-NTH_VALUE-function-over-a-partition-example.png)
In this example,

- The `PARTITION BY` clause to distributed products into product groups (or partitions) specified by the values in the `group_id` column.
- The `ORDER BY` clause sorted the products in each product group from high to low.
- The frame clause defined the whole partition as a frame.
- And the `NTH_VALUE()` function returns the product name of the 2nd row of each product group.

Now, you should how to use the PostgreSQL `NTH_VALUE()` function to get a value from the nth row of a result set.