datarekha
Section 4 chapters · 18 lessons

SQL

From SELECT to window functions, recursive CTEs, and the analytics patterns you'll actually be paid to write. Postgres-first with Snowflake/BigQuery/Redshift notes.

  1. 01

    Foundations

    6 lessons
  2. 01 SELECT basics Beginner 6 min
  3. 02 WHERE & filtering Beginner 6 min
  4. 03 ORDER BY, LIMIT, DISTINCT Beginner 5 min
  5. 04 Aggregates & GROUP BY Beginner 7 min
  6. 05 CASE expressions Beginner 5 min
  7. 06 NULLs done right Intermediate 6 min
  8. 02

    Joins

    3 lessons
  9. 07 INNER JOIN Beginner 6 min
  10. 08 LEFT, RIGHT, FULL Beginner 6 min
  11. 09 Anti-joins Intermediate 5 min
  12. 03

    Advanced Query Building

    5 lessons
  13. 10 Subqueries Intermediate 6 min
  14. 11 CTEs (WITH) Intermediate 7 min
  15. 12 Recursive CTEs Advanced 8 min
  16. 13 Window functions Advanced 10 min
  17. 14 Ranking functions Intermediate 6 min
  18. 04

    Analytics Patterns

    4 lessons
  19. 15 Top-N per group Intermediate 6 min
  20. 16 Deduplication Intermediate 6 min
  21. 17 Cohort analysis Advanced 8 min
  22. 18 Sessionization Advanced 8 min
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