Скачать или смотреть Resolving BigQuery User Defined Function Error - How to Properly Call UDF in Your Queries

Discover how to troubleshoot and resolve the `BigQuery User Defined Function Error` when calling UDFs in queries. Enhance your SQL skills with practical tips!
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Resolving BigQuery User Defined Function Error - How to Properly Call UDF in Your Queries

If you have ever tried using User Defined Functions (UDF) in Google BigQuery, you might have encountered some frustrating errors. One such issue arises when trying to call a UDF within a SQL query. In this guide, we will address a specific problem that can occur during this process and guide you through the solution step by step.

The Problem: Unable to Call UDF in Your Query

In the example we’ll be discussing, a user attempted to call a UDF named CountHolidays within a SELECT statement but faced an error message:

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

This type of error can arise when BigQuery "translates" UDF calls incorrectly, interpreting them in a way that isn’t supported by the SQL query syntax.

Example Scenario

Here’s a look at the UDF defined by the user:

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

And here is how the user attempted to call the UDF:

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

The Solution: Modify the UDF

Understanding the Issue

The error stems from how the UDF interacts with the query’s structure. Specifically, the use of LEFT JOIN without a proper equality condition conflicts with how the function attempts to retrieve data.

Revised UDF

To resolve this error, the UDF needs to be adjusted. Here’s a modified version that should work correctly:

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

Key Changes Made

Parameter Type Change: The START_DATE parameter was changed from DATETIME to DATE. This ensures better compatibility with date functions.

SUM and IF Logic: Instead of wrapping the CASE statement in SUM directly, we used IF to conditionally check whether the CALENDAR_DATE falls within the specified range and handle outputs appropriately.

Conclusion

By adjusting the UDF as explained above, the error related to calling the User Defined Function in a query should be resolved. Always remember to analyze the error messages closely, as they often provide hints on what adjustments are needed.

If you have other queries or challenges regarding BigQuery or managing UDFs, feel free to leave your thoughts in the comments below!