Exploring User Defined Functions in BigQuery

User Defined Functions (UDFs) are powerful tools in BigQuery that allow you to create custom functions to manipulate data. UDFs can be used to perform complex calculations, filter data, or even create custom data types. UDFs are a great way to extend the functionality of BigQuery and make it easier to work with data.

What is a User Defined Function?

A User Defined Function (UDF) is a custom function that you can create in BigQuery. UDFs are written in JavaScript and can be used to perform complex calculations, filter data, or even create custom data types. UDFs are a great way to extend the functionality of BigQuery and make it easier to work with data.

How to Create a User Defined Function in BigQuery

Creating a UDF in BigQuery is easy. First, you need to create a JavaScript file that contains the code for your UDF. This file should be saved in the same directory as your BigQuery project. Once the file is saved, you can use the CREATE FUNCTION statement to create the UDF in BigQuery.


CREATE FUNCTION my_function(x INT64)
RETURNS INT64
LANGUAGE js AS """"""
return x * 2;
""""""

This statement creates a UDF called my_function that takes an INT64 as an argument and returns an INT64. The code for the UDF is written in JavaScript and is enclosed in triple quotes. This code simply multiplies the argument by 2 and returns the result.

Examples of Using User Defined Functions in BigQuery

Once you have created a UDF, you can use it in your BigQuery queries. For example, you can use the UDF to filter data or perform calculations on data. Here is an example of using a UDF to filter data:


SELECT *
FROM my_table
WHERE my_function(column1) > 10

This query will return all rows from my_table where the value of column1 is greater than 10 after being passed through the my_function UDF.

Additional Info about User Defined Functions in BigQuery

User Defined Functions are a great way to extend the functionality of BigQuery and make it easier to work with data. UDFs can be used to perform complex calculations, filter data, or even create custom data types. It's important to note that UDFs are specific to BigQuery and other databases, such as MySQL and PostgreSQL, have their own functions for creating custom functions.

If you want to learn more about UDFs in BigQuery, you can check out the official documentation here.

Ready to write SQL using AI... for Free? 👇👇