Extracting Data from XML in JSON Objects Using Snowflake

Discover how to effectively extract XML data from JSON objects in Snowflake. This post provides a detailed explanation and SQL code to help you avoid null returns.
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Understanding the Challenge: Extracting XML Data from JSON in Snowflake

In the world of data management and analytics, working with nested data formats like JSON and XML can sometimes feel like navigating a complex maze. One common challenge users face is extracting meaningful information from XML sections embedded within JSON objects. This guide addresses a specific case where an XML element exists in a JSON object in Snowflake, and the goal is to extract a particular data field – in this case, the IATA_Number. If you're encountering null returns while trying to achieve this goal, you're not alone! Let's dive into the solution step-by-step.

The Problem

You have the following setup in Snowflake:

A JSON object is stored in a table that contains an XML element.

You encounter issues trying to extract data (like the IATA_Number) from the XML, ending up with null returns instead of the expected values.

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

The Solution: Step-by-Step SQL Code to Extract Data

While dealing with XML can be somewhat daunting, the key is to correctly traverse through the XML hierarchy to access the desired elements. Below is a breakdown of the SQL code designed to help you extract the IATA_Number from the XML within your JSON object.

Step 1: Parse the XML

To start, you will need to parse the XML from the JSON field. This requires using the PARSE_XML function on the relevant column. We will create a Common Table Expression (CTE) for clarity.

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

Step 2: Extract Specific XML Elements

From the parsed XML, you can progressively extract each element. You'll reference the previous extraction results as you traverse the hierarchy down to the IATA_Number. Here’s how to do it:

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

Explanation of the Code

CTE Structure: The cte1 section establishes a baseline where the XML data is extracted as a variant for further querying.

Progressive Extraction: By separating each level of hierarchy into distinct variables (L1, L2, L3, L4, L5), we make the code more readable and easier to debug.

Final Extraction: The final line retrieves the desired IATA_Number by referencing the extracted TravelAgencySender.

Conclusion

Extracting XML data from JSON objects in Snowflake is achievable through careful hierarchy traversal. By following the structured approach outlined in this guide, you can successfully retrieve the information you need without encountering null values. Remember, when dealing with more complex structures, you may need to incorporate LATERAL FLATTEN for repeating elements. Happy querying!