Types

interview preparation

Common Window Functions

1. Ranking
   • ROW_NUMBER(): Assigns a unique number to each row.
   • RANK(): Assigns ranks; ties get the same rank.
   • DENSE_RANK(): Similar to RANK(), but no gaps between ranks.
2. Aggregates:
   • SUM(), AVG(), MIN(), MAX(), COUNT(): Works across the window.
3. Analytics:
   • LAG() and LEAD(): Access values from previous or next rows.
   • FIRST_VALUE() and LAST_VALUE(): Get the first or last value in the window.
4. Percentages:
   • PERCENT_RANK(): Rank as a percentage.
   • NTILE(n): Divides rows into n buckets.