How to Concat Variables with Strings and Insert into JSONB in PostgreSQL

A detailed guide on how to concatenate variables with strings and insert them into a JSONB column in PostgreSQL using json_build_object for seamless integration.
---

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: postgresql concat variable with string and insert into JSONB

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Mastering JSONB in PostgreSQL: Concatenating Variables with Strings

When working with PostgreSQL, you may sometimes face challenges with JSONB columns, especially when trying to concatenate a variable with a string to construct JSON. In this post, we’ll dive into a common scenario: inserting a concatenated value into a JSONB column and how to do it correctly without running into syntax errors. Let's explore the issue and its solution in detail.

The Problem

Imagine you need to insert a JSON object into a table and the JSON contains a dynamic value derived from a variable. One might attempt to directly concatenate this variable with a string while constructing a JSON string. Here's a sample query that is often used but may produce errors:

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

The above query might result in an error like ERROR: syntax error at or near "INSERT". This error arises from the way we are attempting to concatenate variables within a JSON string, which is not the ideal approach in PostgreSQL.

The Solution

To effectively insert a concatenated variable into a JSONB column, one of the best practices is to use the json_build_object function. This built-in PostgreSQL function allows you to construct JSON objects more cleanly and with fewer chances of syntax errors. Here’s how to do it:

Step-by-step Instructions

Declare the Variable: Start by declaring the integer variable that you want to insert into the JSON.

Build the JSON Object: Use json_build_object to prepare your JSON data, including the dynamic variable directly in the function's parameters.

Insert the Data: Finally, use an INSERT statement to add the constructed JSON into your desired table.

Example Query

Here's the revised version of the query using the json_build_object function:

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

Breakdown of the Solution:

Variable Declaration: The integer variable myID is assigned the value 555.

JSON Object Creation: The json_build_object function is called with key-value pairs. Here, we include the myID variable directly in the pageUrl value part.

Insertion: The JSON object myJson is then inserted into the url column of the mytable, along with some status code 0.

Conclusion

Using json_build_object not only simplifies the process of constructing JSON but also helps avoid common syntax errors associated with string concatenation in SQL. By following the outlined steps, you can efficiently insert dynamic values into JSONB fields, enhancing the flexibility and capability of your PostgreSQL databases.

Feel free to implement this method in your queries and enjoy a smoother experience working with JSON in PostgreSQL!