Handling Missing Primary Keys for Derived Columns: The LAG/LEAD Puzzle in SQL Server 2012

Solving Duplicates in Time Periods from Repeated Groups Using SQL Analytics

Finding Missing Numbers in a Sequence: A Recursive Approach

Combining Duplicate Records Based on Column Combinations: A SQL Approach

Running Totals from Consecutive Columns: A Flexible Approach to Gaps and Islands

SQL Join Against Date Ranges: Exploring Consecutive Dates with LAG, DATEDIFF, and Grouping