Window Functions and Time Series Analytics Questions

Advanced SQL window functions: ROW_NUMBER, RANK, DENSE_RANK, LAG, LEAD, and aggregate functions (SUM, COUNT, AVG) with OVER and partition clauses. Using window functions to solve practical problems: ranking users or events within segments, calculating running totals and cumulative metrics, identifying trends and transitions over time, detecting patterns in user behavior sequences. Applications: cohort retention analysis (calculating retention rates across cohorts), user lifetime value trends, engagement metrics over time windows, and sequential user actions.