---
title: 'PostgreSQL jsonb_array_elements() Function'
page_title: 'PostgreSQL jsonb_array_elements() Function'
page_description: 'How to use the PostgreSQL jsonb_array_elements() function to expand the top-level JSON array into a set of JSON values.'
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updatedOn: '2024-02-24T04:18:19+00:00'
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---

**Summary**: in this tutorial, you will learn how to use the PostgreSQL `jsonb_array_elements()` function to expand the top\-level JSON array into a set of JSON values.

## Introduction to the PostgreSQL jsonb_array_elements() function

The `jsonb_array_elements()` function allows you to expand the top\-level [JSON](../postgresql-tutorial/postgresql-json) array into a set of JSON values.

Here’s the basic syntax of the `jsonb_array_elements()` function:

```sql
jsonb_array_elements(json_array)
```

In this syntax, you specify a JSON array with a JSONB type that you want to expand its elements.

The `jsonb_array_elements()` function will expand the elements of the `json_array` into individual elements.

If you pass a non\-array to the function, it’ll issue an error. If the `json_array` is `NULL`, the function returns an empty result set.

## PostgreSQL jsonb_array_elements() function examples

Let’s explore some examples of using the `jsonb_array_elements()` function.

### 1\) Basic PostgreSQL jsonb_array_elements() function examples

The following example uses the `jsonb_array_elements()` function to expand elements of a JSON array:

```sql
SELECT jsonb_array_elements('[1,2,3]');
```

Output:

```text
 jsonb_array_elements
----------------------
 1
 2
 3
(3 rows)
```

Note that the numbers 1, 2, 3 are the JSON values.

The following example uses the `jsonb_array_elements()` function to expand an array of strings:

```sql
SELECT jsonb_array_elements('["red","green","blue"]');
```

Output:

```text
 jsonb_array_elements
----------------------
 "red"
 "green"
 "blue"
(3 rows)
```

### 2\) Using the jsonb_array_elements() function with nested arrays example

The following example uses the `jsonb_array_elements()` function to expand elements of an array that contains another array:

```sql
SELECT jsonb_array_elements('[1,2,3, [4,5], 6]');
```

Output:

```text
 jsonb_array_elements
----------------------
 1
 2
 3
 [4, 5]
 6
(5 rows)
```

### 3\) Using the jsonb_array_elements() function with table data

First, [create a table](../postgresql-tutorial/postgresql-create-table) called `employees`:

```sql
CREATE TABLE employees (
    id SERIAL PRIMARY KEY,
    name VARCHAR(100) NOT NULL,
    skills JSONB
);
```

The `skills` column has the JSONB type, which stores the skills of employees.

Second, [insert some rows](../postgresql-tutorial/postgresql-insert-multiple-rows) into the `employees` table:

```sql
INSERT INTO employees (name, skills)
VALUES
('John Doe', '["Java", "Python", "SQL"]'),
('Jane Smith', '["C++", "JavaScript", "HTML/CSS"]'),
('Alice Johnson', '["Python", "Data Analysis", "Machine Learning"]'),
('Bob Brown', '["Java", "SQL", "Spring Framework"]');
```

Third, retrieve all skills of employees:

```sql
SELECT jsonb_array_elements(skills) skills
FROM employees;
```

Output:

```text
       skills
--------------------
 "Java"
 "Python"
 "SQL"
 "C++"
 "JavaScript"
 "HTML/CSS"
 "Python"
 "Data Analysis"
 "Machine Learning"
 "Java"
 "SQL"
 "Spring Framework"
(12 rows)
```

It returns 12 skills.

It’s possible to use the [`DISTINCT`](../postgresql-tutorial/postgresql-select-distinct) to get unique skills of all employees:

```sql
SELECT DISTINCT jsonb_array_elements(skills) skills
FROM employees;
```

Output:

```text
       skills
--------------------
 "C++"
 "Python"
 "SQL"
 "HTML/CSS"
 "JavaScript"
 "Java"
 "Data Analysis"
 "Spring Framework"
 "Machine Learning"
(9 rows)
```

## Summary

- Use the `jsonb_array_elements()` function to expand elements of the top\-level JSON array.