SQL-Practice-Problems-solution

This is my solution to Sylvia moestl vasilik SQL practice problems

About the book

The SQL practice problems consist of 57 select statement problems which ranges from beginners level select statement to advanced level select statement. Getting practice on real life data can be hard without working as a data analyst, engineer or programmer and the best way to learn is by practicing, so this book was written to introduce data enthusiasts to real life data problems.

A modified northwind database was used for this book. But the solution here is based on Microsoft sample Northwind database.

The 57 practice problems solved in this project include:

Introductory Problems

1. Which shippers do we have?
2. Certain fields from Categories
3. Sales Representatives
4. Sales Representatives in the United States
5. Orders placed by specific EmployeeID
6. Suppliers and ContactTitles
7. Products with “queso” in ProductName
8. Orders shipping to France or Belgium
9. Orders shipping to any country in Latin America
10. Employees, in order of age
11. Showing only the Date with a DateTime field
12. Employees full name
13. OrderDetails amount per line item
14. How many customers?
15. When was the first order?
16. Countries where there are customers
17. Contact titles for customers
18. Products with associated supplier names
19. Orders and the Shipper that was used

Intermediate Problems

20. Categories, and the total products in each category
21. Total customers per country/city
22. Products that need reordering
23. Products that need reordering, continued
24. Customer list by region
25. High freight charges
26. High freight charges - 2015
27. High freight charges with between
28. High freight charges - last year
29. Inventory list
30. Customers with no orders
31. Customers with no orders for EmployeeID 4

Advanced Problems

32. High-value customers
33. High-value customers - total orders
34. High-value customers - with discount
35. Month-end orders
36. Orders with many line items
37. Orders - random assortment
38. Orders - accidental double-entry
39. Orders - accidental double-entry details
40. Orders - accidental double-entry details, derived table
41. Late orders
42. Late orders - which employees?
43. Late orders vs. total orders
44. Late orders vs. total orders - missing employee
45. Late orders vs. total orders - fix null
46. Late orders vs. total orders - percentage
47. Late orders vs. total orders - fix decimal
48. Customer grouping
49. Customer grouping - fix null
50. Customer grouping with percentage
51. Customer grouping - flexible
52. Countries with suppliers or customers
53. Countries with suppliers or customers, version 2
54. Countries with suppliers or customers - version 3
55. First order in each country
56. Customers with multiple orders in 5 day period
57. Customers with multiple orders in 5 day period, version 2