Danny’s Diner

Data exploration using mySQL

This is a guided case study where I use SQL skills to answer the first part of 8 week SQL challenge posted by Danny Ma.

This case study is based on a restaurant, you can find it here and try it yourself. My solution is also hosted on my Git Hub and you can access it here.

SQL skills that I honed while doing the case study

• JOINS
• ALIASES — used more frequently as I practised
• WINDOW FUNCTION — Rank
• CTE (Common Table Expressions)
• CASE STATEMENTS

Question 1 — What is the total amount each customer spent at the restaurant?

Question 2 — How many days has each customer visited the restaurant?

Question 3 - What was the first item from the menu purchased by each customer?

Question 4 — What is the most purchased item on the menu
and how many times was it purchased by all customers?

Question 5 — Which item was the most popular for each customer?

Question 6 — Which item was purchased first by the customer after they became a member?

Question 7 — Which item was purchased just before the customer became a member?

Question 8 — What is the total items and amount spent for each member before they became a member?

Question 9 - if each $1 spent equates to 10 points and sushi has a 2x points multiplier — how many points would each customer have?

Question 10 — In the first week after a customer joins the program (including their join date) they earn 2x points on all items, not just sushi — how many points do customer A and B have at the end of January?

Bonus question 1 — Join All The Things

Bonus Question 2 — Rank All The Things

Thank you for reading! Let me if you have any queries about my solutions!