Feature preprocessing overview

Feature preprocessing is one of the most important steps in developing a machine learning model. It consists of the creation of features as well as the cleaning of the data. Sometimes, the creation of features is also referred as "feature engineering".

Feature preprocessing offerings

BigQuery ML supports two types of feature preprocessing:

  • Automatic preprocessing. BigQuery ML performs automatic preprocessing during training. For more information, see Automatic feature preprocessing.
  • Manual preprocessing. BigQuery ML provides the TRANSFORM clause for you to define custom preprocessing using the manual preprocessing functions. You can also use these functions outside the TRANSFORM clause.

Additionally, you can use the ML.FEATURE_INFO function to retrieve the statistics of all input feature columns.