SQL window functions separate mid-level from senior developers

Short summary

Window functions let you compute aggregates without collapsing rows—preserving individual records while adding group context. Learn ROW_NUMBER(), RANK/DENSE_RANK, LAG/LEAD, frame clauses, and rolling aggregates through practical SQL examples. These patterns distinguish mid-level queries from senior-level database work.

• •Window functions compute aggregates over row sets while keeping individual rows intact, unlike GROUP BY
• •Master key functions: ROW_NUMBER, RANK/DENSE_RANK, LAG/LEAD, FIRST/LAST_VALUE, and NTILE with runnable examples
• •Use frame clauses (ROWS/RANGE) for running totals and moving averages without subqueries or cursors

Generated with AI, which can make mistakes.