Data deduplication is a crucial step in data engineering to ensure clean and accurate datasets. In Databricks (Apache Spark SQL), Window Functions help identify duplicate records by assigning a rank or row number to each row within a partition. Traditionally, ROW_NUMBER() is used along with a subquery or Common Table Expression (CTE) to remove duplicates.
With the QUALIFY clause, Databricks simplifies this process by filtering window function results directly in the SQL query, eliminating the need for subqueries.
