Is there a way to parse XML tags in BigQuery Standard SQL?

Question

I have read that it's a bad idea to parse XML/HTML using regular expressions. The alternative suggestion is to use an XML parser. Does one exist in the BigQuery Standard SQL library?

Answer 1

Here is the documentation to how to use Javascript UDFs in BigQuery like Elliot has mentioned.

https://cloud.google.com/bigquery/docs/reference/standard-sql/user-defined-functions

I imagine the UDF might look something like

CREATE TEMPORARY FUNCTION XML(x STRING)
RETURNS STRING
  LANGUAGE js AS """
  var data = fromXML(x);
  return data.title;
"""
OPTIONS(
library="gs://<BUCKET_NAME>/from-xml.min.js"
);
SELECT XML(a) FROM UNNEST(["<title>Title of Page</title>"]) as a

Where from-xml.min.js is from this library and loaded into your gcs account