Getting Blank Values while extracting data from list of JSON in String column using AWS Athena
Tags: json, amazonathena, presto
Published: 2023-08-31 14:59:50

Have you ever encountered a situation where you were extracting data from a list of JSON in a String column using AWS Athena, only to find yourself getting blank values? Don't worry, you're not alone! This article will guide you through the process of dealing with this issue and help you get the data you need.

Before we dive into the solution, let's understand the problem a bit better. AWS Athena is a powerful query service that allows you to analyze data directly from Amazon S3 using SQL. However, when dealing with JSON data stored in a String column, extracting the values can sometimes be tricky. It's not uncommon to run into situations where the extracted values turn out to be blank.

So, why does this happen? Well, the most common reason is that the JSON data in the String column is not properly formatted. It could be missing key-value pairs, have incorrect syntax, or contain nested structures that are not handled correctly. These issues can cause Athena to fail in extracting the desired values, resulting in blank values.

Now, let's move on to the solution. To overcome this problem, you need to ensure that your JSON data is correctly formatted and that you are using the appropriate functions to extract the values. Here are a few steps you can follow:

1.  Validate your JSON data: Use a JSON validator tool to check if your JSON data is properly formatted. Fix any errors or missing elements in the JSON structure.
2.  Use the `json\_extract\_scalar` function: This function is specifically designed to extract scalar values from a JSON structure. Make sure you are using this function instead of other generic JSON functions.
3.  Handle nested structures: If your JSON data contains nested structures, you need to use the appropriate functions to extract the values from those structures. For example, you can use `json\_extract\_scalar` for scalar values and `json_extract` for nested objects or arrays.
4.  Check for null values: Sometimes, the extracted values may be null instead of blank. Make sure to handle null values in your queries to avoid any unexpected results.

By following these steps, you should be able to successfully extract the desired values from your JSON data using AWS Athena. Remember, patience and a sense of humor can go a long way in troubleshooting technical issues. So, don't forget to keep a few funny phrases handy to lighten the mood!

Conclusion
----------

Extracting data from a list of JSON in a String column using AWS Athena can be challenging, but with the right approach, you can overcome this hurdle. By validating your JSON data, using the appropriate functions, handling nested structures, and checking for null values, you can ensure that you get the data you need without any blank values. So, roll up your sleeves, follow these steps, and get ready to conquer the JSON extraction challenge!

References
----------

*   [AWS Athena](https://aws.amazon.com/athena/)
*   [Extracting Data from JSON in Athena](https://docs.aws.amazon.com/athena/latest/ug/extracting-data-from-JSON.html)
*   [JSON Validator](https://jsonlint.com/)

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