To discover records in one table that are not present in another, you can utilize a LEFT JOIN and filter out any NULL values in the right-side table. For example, say you had a table of Databricks customers and a 2nd table of all purchases made with Databricks. To find all customers who did not make a purchase, you'd use the following LEFT JOIN SELECT * FROM customers c LEFT JOIN purchases p ON c.id = p.customer_id WHERE p.id IS NULL; This query fetches all rows from the customers table, along with any rows that match in the purchases table. If there is no matching row in the purchases table, NULL values will be returned for all of the right table's columns. The WHERE clause then filters out any rows where the purchases.id column is NULL, leaving only customers who have not made a purchase. ---