Aggregation
- GROUP BY & Aggregates β Compute counts and sums; HAVING for post-aggregate filters.
- π§ HAVING vs WHERE β Pre-aggregate vs post-aggregate filtering.
- π§ Window Basics β ROW_NUMBER, RANK, DENSE_RANK.
- π§ Window Aggregates β SUM() OVER, running totals, moving averages.
- π§ Window Frames β ROWS vs RANGE, peers, gaps & islands.
- π§ Grouping Sets β ROLLUP, CUBE, and GROUPING SETS.