Master the gaps-and-islands pattern, one of SQL's most versatile techniques for analyzing time-series data. This tutorial demonstrates how to identify continuous periods (islands) and breaks (gaps) in overlapping events, from hotel booking clusters to network alarm sequences. Learn to use window functions like LAG() and running sums with CTEs to solve real-world problems in network monitoring, user session analysis, server uptime tracking, and equipment maintenance scheduling. Includes complete working examples you can run immediately in PostgreSQL or MySQL.