How to Convert a JSONB Field's Value into a JSON Array in PostgreSQL

Learn how to convert JSONB field values into a JSON array in PostgreSQL with a simple SQL example.
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How to Convert a JSONB Field's Value into a JSON Array in PostgreSQL

When working with databases, you may find yourself in need of transforming your data into different formats for various use cases. One common scenario arises in PostgreSQL, when you want to convert values in a JSONB field into a more manageable JSON array format. This task can enhance data visualization, manipulation, and retrieval quite significantly. In this guide, we’ll guide you through the steps needed to achieve this transformation in an efficient manner.

The Problem

Imagine you have a table with a JSONB column that contains individual JSON objects. For instance, consider a table named test, which stores information about names in the JSONB format. The structure of this table might look something like this:

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You then insert several values into this table:

[[See Video to Reveal this Text or Code Snippet]]

Now, you want to retrieve these records as a single JSON array that looks like this:

[[See Video to Reveal this Text or Code Snippet]]

The goal is to convert the individual JSONB records into a cohesive JSON array. How do you accomplish this in SQL? Let’s take a closer look at the solution.

The Solution

To transform the JSONB field values into an array, you can utilize the built-in PostgreSQL functions. Below are the steps and SQL code needed to obtain the desired JSON array format.

Step 1: Create and Insert Values into the Test Table

First, ensure that your test table is defined and populated as shown earlier.

[[See Video to Reveal this Text or Code Snippet]]

Step 2: Use JSONB Aggregation Function

PostgreSQL has a handy function called jsonb_agg() which can be utilized to aggregate JSONB values into a JSON array.

Here’s the SQL query you would use:

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This command will return the result in the format you want:

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Alternative: Native PostgreSQL Array

If you need a native PostgreSQL array instead of a JSON array, you can use the array_agg() function. The syntax looks like this:

[[See Video to Reveal this Text or Code Snippet]]

This will return an array format that PostgreSQL can work with natively.

Conclusion

In summary, converting JSONB fields into a JSON array in PostgreSQL is a straightforward process using the jsonb_agg() function. Whether you require the formatted output for reporting purposes or for further data manipulation, these SQL queries allow you to achieve your objectives effectively.

With this transformation knowledge under your belt, you're now equipped to handle similar data organization challenges in PostgreSQL. Happy querying!