SQL Aggregate vs. Window Functions: Key Differences Explained

SQL features both aggregate and window functions for data analysis. Aggregate functions, such as SUM or AVG, combine multiple rows of data into a single summarized result, often reducing the total number of rows. In contrast, window functions perform calculations across a set of rows while preserving each individual row in the output. This fundamental difference is crucial for data professionals when choosing the right tool for summarizing versus analyzing data within its original context. Understanding when to use GROUP BY with aggregates versus the OVER clause with window functions is key to effective SQL querying.