PrestoML allows users to perform machine learning tasks like classification and regression directly in SQL queries using Presto. It works by adding machine learning functions as Presto plugins that can be called from SQL. This allows ML tasks to be integrated with querying and analysis of data stored in databases and other data sources. Some key benefits are that ML code does not need to be written separately, and ML models can be stored directly as tables to be queried. The demo shows classifying emails as spam by learning a model directly from a SQL query. Future work may include more algorithms, hyperparameter tuning, and other ML techniques.