Data Analysis - Analytic problem solving with SQL and Pandas

Looking for a more bite-sized approach to improve your analytical and data engineering skills over time? This problem set is for you!

The following problems will give you analytics based scenarios that you need to solve with either SQL or Pandas.

Completing this problem set WILL make you a better data engineer and data analyst.

The problems will give you the tools to more efficiently work with large datasets and come up with code to automate your analysis.

All problems listed below come from https://www.stratascratch.com/.

StrataScratch is an excellent resource to find technical questions and exercises utilized in Data Engineering and Data Analyst interviews at top companies like Microsoft, Google, Meta, and more.

Don't try to complete the entire list of problems all in one sitting. Take the time to dig into each question.

We recommend you focus on 1-2 problems a day.

Take the time to study the solutions to the problem, and understand how each part of the solution code works.

How to engage with these problems

When taking on these problems, you should try to solve them on your own for 15-20 minutes, but no longer than that. Not knowing the answer is fine. You want to ensure you give yourself time to work your brain to solve it, but not waste time if you just don't have the knowledge.

After 15-20 minutes, you can then view other peoples solutions in the "Solutions" tab in the LeetCode window. When you view the solution, you should then take the time (at least 25 minutes at a time) to understand how the solution works, adding it to your own code window and changing pieces of it to help understand what each part does. Then, take a 5 minute break. After that break, come back and try to solve the problem on your own again with no help.

Data Analysis - Dataset Analysis

You may use any SQL variant available or Python-Pandas to solve these problems. Use the dropdown in the top left corner of the window to change the language used for the question and any displayed solutions.

https://platform.stratascratch.com/coding?job_positions=1&job_positions=3&job_positions=4&is_freemium=1&code_type=5&order_field=difficulty&page_size=100

Sequence	Difficulty	Problem Name	Link to StrataScratch Problem
1	Easy	Unique Users Per Client Per Month	Link To StrataScratch Problem
2	Easy	Number of Shipments Per Month	Link To StrataScratch Problem
3	Easy	Most Lucrative Products	Link To StrataScratch Problem
4	Easy	Number Of Bathrooms And Bedrooms	Link To StrataScratch Problem
5	Easy	Count the number of user events performed by MacBookPro users	Link To StrataScratch Problem
6	Easy	Find the most profitable company in the financial sector of the entire world along with its continent	Link To StrataScratch Problem
7	Easy	Churro Activity Date	Link To StrataScratch Problem
8	Easy	Admin Department Employees Beginning in April or Later	Link To StrataScratch Problem
9	Easy	Number of Workers by Department Starting in April or Later	Link To StrataScratch Problem
10	Easy	Customer Details	Link To StrataScratch Problem
11	Easy	Order Details	Link To StrataScratch Problem
12	Easy	Average Salaries	Link To StrataScratch Problem
13	Easy	Find libraries who haven't provided the email address in circulation year 2016 but their notice preference definition is set to email	Link To StrataScratch Problem
14	Easy	Find the base pay for Police Captains	Link To StrataScratch Problem
15	Easy	Find how many times each artist appeared on the Spotify ranking list	Link To StrataScratch Problem
16	Easy	Lyft Driver Wages	Link To StrataScratch Problem
17	Easy	Popularity of Hack	Link To StrataScratch Problem
18	Easy	Find all posts which were reacted to with a heart	Link To StrataScratch Problem
19	Easy	Abigail Breslin Nominations	Link To StrataScratch Problem
20	Easy	Reviews of Hotel Arena	Link To StrataScratch Problem
21	Easy	Bikes Last Used	Link To StrataScratch Problem
22	Easy	Finding Updated Records	Link To StrataScratch Problem
23	Easy	Salaries Differences	Link To StrataScratch Problem
24	Medium	Share of Active Users	Link To StrataScratch Problem
25	Medium	Premium Acounts	Link To StrataScratch Problem
26	Medium	Election Results	Link To StrataScratch Problem
27	Medium	Flags per Video	Link To StrataScratch Problem
28	Medium	User with Most Approved Flags	Link To StrataScratch Problem
29	Medium	Find students with a median writing score	Link To StrataScratch Problem
30	Medium	Find the top 10 ranked songs in 2010	Link To StrataScratch Problem
31	Medium	Classify Business Type	Link To StrataScratch Problem
32	Medium	Number of violations	Link To StrataScratch Problem
33	Medium	Find the rate of processed tickets for each type	Link To StrataScratch Problem
34	Medium	Customer Revenue In March	Link To StrataScratch Problem
35	Medium	Find the number of times each word appears in drafts	Link To StrataScratch Problem
36	Medium	Make a report showing the number of survivors and non-survivors by passenger class	Link To StrataScratch Problem
37	Medium	Second Highest Salary	Link To StrataScratch Problem
38	Medium	Employee and Manager Salaries	Link To StrataScratch Problem
39	Medium	Highest Salary In Department	Link To StrataScratch Problem
40	Medium	Highest Target Under Manager	Link To StrataScratch Problem
41	Medium	Highest Cost Orders	Link To StrataScratch Problem
42	Medium	Largest Olympics	Link To StrataScratch Problem
43	Medium	Top Ranked Songs	Link To StrataScratch Problem
44	Medium	Find all wineries which produce wines by possessing aromas of plum, cherry, rose, or hazelnut	Link To StrataScratch Problem
45	Medium	Top Businesses With Most Reviews	Link To StrataScratch Problem
46	Medium	Reviews of Categories	Link To StrataScratch Problem
47	Medium	Top Cool Votes	Link To StrataScratch Problem
48	Medium	Highest Energy Consumption	Link To StrataScratch Problem
49	Medium	Income By Title and Gender	Link To StrataScratch Problem
50	Medium	Matching Similar Hosts and Guests	Link To StrataScratch Problem
51	Medium	Find the percentage of shipable orders	Link To StrataScratch Problem
52	Medium	Spam Posts	Link To StrataScratch Problem
53	Medium	Apple Product Counts	Link To StrataScratch Problem
54	Medium	No Order Customers	Link To StrataScratch Problem
55	Medium	Number Of Units Per Nationality	Link To StrataScratch Problem
56	Medium	Ranking Most Active Guests	Link To StrataScratch Problem
57	Medium	Acceptance Rate By Date	Link To StrataScratch Problem
58	Medium	Clicked Vs Non-Clicked Search Results	Link To StrataScratch Problem
59	Medium	Meta/Facebook Accounts	Link To StrataScratch Problem
60	Medium	Risky Projects	Link To StrataScratch Problem
61	Medium	New Products	Link To StrataScratch Problem
62	Medium	Finding User Purchases	Link To StrataScratch Problem
63	Medium	Activity Rank	Link To StrataScratch Problem
64	Medium	Users By Average Session Time	Link To StrataScratch Problem
65	Medium	Workers With The Highest Salaries	Link To StrataScratch Problem
66	Medium	Most Profitable Companies	Link To StrataScratch Problem
67	Hard	Marketing Campaign Success [Advanced]	Link To StrataScratch Problem
68	Hard	The Most Popular Client_Id Among Users Using Video and Voice Calls	Link To StrataScratch Problem
69	Hard	Retention Rate	Link To StrataScratch Problem
70	Hard	Cookbook Recipes	Link To StrataScratch Problem
71	Hard	Host Popularity Rental Prices	Link To StrataScratch Problem
72	Hard	City With Most Amenities	Link To StrataScratch Problem
73	Hard	Counting Instances in Text	Link To StrataScratch Problem
74	Hard	Top 5 States With 5 Star Businesses	Link To StrataScratch Problem
75	Hard	Popularity Percentage	Link To StrataScratch Problem
76	Hard	Premium vs Freemium	Link To StrataScratch Problem
77	Hard	Top Percentile Fraud	Link To StrataScratch Problem
78	Hard	Monthly Percentage Difference	Link To StrataScratch Problem