This document discusses modern SQL features including common table expressions (CTE), lateral joins, window functions, recursive CTE, and hierarchical queries. It provides examples of how to return the last performance review of each employee, the last two reviews, a table with cumulative salary, percentage of salary by department, and generating an organizational hierarchy using recursive CTE. Key database implementations of these features include DB2, SQL Server, PostgreSQL, and Oracle, with SQLite and MySQL supporting some or none of the modern SQL features.

1. Modern SQL
Regis Hideki Hattori

2. Introduction

3. Introduction
● DB2, SQL Server, Postgres and Oracle implement almost all of them

4. Introduction
● DB2, SQL Server, Postgres and Oracle implement almost all of them
● SQLite implements some of them

5. Introduction
● DB2, SQL Server, Postgres and Oracle implement almost all of them
● SQLite implements some of them
● MySQL implements none of them

6. Tables
performance_reviewsemployees

7. Filter
How many performance reviews per year?

8. Filter
How many performance reviews per year?

9. Filter
How many performance reviews per year?

10. “What are the last
performance review of
each employee?”

11. Last performance review of each employee

12. Last Performance Review by Employee

13. Last Performance Review by Employee

14. Last Performance Review by Employee

15. Last Performance Review by Employee

16. CTE (Common Table Expressions)

17. CTE

18. CTE
is like a private method

19. “What are the 2 last
performance reviews of
each employee?”

20. Last 2 performance reviews of each employee

21. What we need to change?

22. Lateral Join

23. Lateral Join

24. Lateral Join

25. Lateral Join

26. Lateral Join
It is like a foreach...

27. “We need a table with a
cumulative salary.”

28. Over (Window functions)

29. Over (Window functions)

30. Over (Window functions)

31. Over (Window functions)

32. “What is the percentage of
salary of each employee
by department?”

33. Over + Partition

34. Over + Partition

35. Over + Partition

36. Over + Partition

37. Over + Partition

38. Over + Partition

39. “I want a vision of our
hierarchy”

40. Hierarchy

41. Hierarchy

42. CTE recursive

43. CTE recursive

44. CTE recursive

45. CTE recursive

46. CTE recursive

47. CTE recursive

48. References
● https://modern-sql.com/
● http://stackoverflow.com/questions/3699395/find-parent-
recursively-using-query
● http://www.postgresql.org/docs/8.4/static/functions-
window.html
● https://www.youtube.com/watch?v=ogVka4KzE6s

49. Thanks