ravisekharr/datalemur

SQL practice problems from https://datalemur.com/

DataLemur

SQL practice problems from https://datalemur.com?referralCode=6GoZJBkG

Day	Problem	Concepts	Level	Link
Day1	Data Science Skills	IN, GROUP BY	Easy	https://datalemur.com/questions/matching-skills
	Laptop vs Mobile Viewership	SUM, CASE WHEN	Easy	https://datalemur.com/questions/laptop-mobile-viewership
	User's Third Transaction	ROW_NUMBER(), PARTITION BY()	Medium	https://datalemur.com/questions/sql-third-transaction
Day2	Active User Retention	LAG(), PARTITION BY()	Hard	https://datalemur.com/questions/user-retention
	Page With No Likes	NOT IN	Easy	https://datalemur.com/questions/sql-page-with-no-likes
	Sending vs. Opening Snaps	GROUP BY, JOIN	Medium	https://datalemur.com/questions/time-spent-snaps
Day3	Tweets' Rolling Averages	PARTITION BY, ROWS BETWEEN PRECEDING CURRENT ROW	Medium	https://datalemur.com/questions/rolling-average-tweets
	Unfinished Parts	IS NULL	Easy	https://datalemur.com/questions/tesla-unfinished-parts
	Y-on-Y Growth Rate	LAG(), PARTITION BY()	Hard	https://datalemur.com/questions/yoy-growth-rate
Day4	Average Post Hiatus (Part 1)	DATE EXTRACT	Easy	https://datalemur.com/questions/sql-average-post-hiatus-1
	Median Google Search	CASE WHEN, CTE, GENERATE_SERIES, PERCENTILE_CONT, WITHIN GROUP	Hard	https://datalemur.com/questions/median-search-freq
	Top 5 Artists	DENSE_RANK(), JOIN	Medium	https://datalemur.com/questions/top-fans-rank
Day5	Duplicate Job Listings	DISTINCT COUNT, GROUP BY	Easy	https://datalemur.com/questions/duplicate-job-listings
	Highest-Grossing Items	ROW_NUMBER(), PARTITION BY(), DATE EXTRACT	Medium	https://datalemur.com/questions/sql-highest-grossing
	Maximize Prime Item Inventory	CTE, CASE WHEN	Hard	https://datalemur.com/questions/prime-warehouse-storage
Day6	Advertiser Status	CASE WHEN	Hard	https://datalemur.com/questions/updated-status
	Signup Activation Rate	CASE WHEN	Medium	https://datalemur.com/questions/signup-confirmation-rate
	Teams Power Users	GROUP BY, DATE EXTRACT	Easy	https://datalemur.com/questions/teams-power-users
Day7	3-Topping Pizzas	CTE,Self join	HARD	https://datalemur.com/questions/pizzas-topping-cost
	Fill Missing Client Data	JOIN, ROW_NUMBER()	Medium	https://datalemur.com/questions/fill-missing-product
	Cities with completed trade	JOIN, GROUP BY	Easy	https://datalemur.com/questions/completed-trades
Day8	Patient Support Analysis (Part 3)	CTE,LEAD/LAG	Hard	https://datalemur.com/questions/patient-call-history
	Average Review Ratings	GROUP BY,EXTRACT,AVG	Easy	https://datalemur.com/questions/sql-avg-review-ratings
	Frequently Purchased Pairs	SELF JOIN	Medium	https://datalemur.com/questions/frequently-purchased-pairs
Day9	App Click-through Rate	GROUP BY,EXTRACT,COUNT	Easy	https://datalemur.com/questions/click-through-rate
	Supercloud Customer	JOIN,COUNT	Medium	https://datalemur.com/questions/supercloud-customer
	Patient Support Analysis (Part 4)	GROUP BY,LAG,CTE,EXTRACT	Hard	https://datalemur.com/questions/long-calls-growth
Day10	Second Day Confirmation	JOIN,EXTRACT	Easy	https://datalemur.com/questions/second-day-confirmation
	Odd and Even Measurements	CTE,ROW_NUMBER,SUM,GROUP BY	Medium	https://datalemur.com/questions/odd-even-measurements
	Repeated Payments	CTE,LAG,EXTRACT	Hard	https://datalemur.com/questions/repeated-payments
Day11	Compressed Mean	ROUND,SUM	Easy	https://datalemur.com/questions/alibaba-compressed-mean
	Compressed Mode	MAX	Medium	https://datalemur.com/questions/alibaba-compressed-mode
	Cards Issued Difference	MIN,MAX,GROUP BY	Easy	https://datalemur.com/questions/cards-issued-difference
	Card Launch Success	CTE,ROW_NUMBER,PARTITION BY	Medium	https://datalemur.com/questions/card-launch-success
Day12	Histogram of Users and Purchases	CTE,PARTITION BY,RANK,GROUP BY	Medium	https://datalemur.com/questions/histogram-users-purchase
	International Call Percentage	CTE,JOIN	Medium	https://datalemur.com/questions/international-call-percentage
	Patient Support Analysis (Part 1)	GROUP BY,COUNT	Easy	https://datalemur.com/questions/frequent-callers
	Patient Support Analysis (Part 2)	FILTER,COUNT	Easy	https://datalemur.com/questions/uncategorized-calls-percentage
Day13	Pharmacy Analytics (Part 1)	GROUP BY,LIMIT	Easy	https://datalemur.com/questions/top-profitable-drugs
	Pharmacy Analytics (Part 2)	GROUP BY,LIMIT	Easy	https://datalemur.com/questions/non-profitable-drugs
	Pharmacy Analytics (Part 3)	GROUP BY,CONCAT	Easy	https://datalemur.com/questions/total-drugs-sales
Day14	Average Deal Size (Part 1)	AVG,ROUND	Easy	https://datalemur.com/questions/sql-average-deal-size
	Best-Selling Product	RANK,PARTITION BY,JOIN	Medium	https://datalemur.com/questions/best-selling-products
	Rolling 3-Day Earnings	RANGE BETWEEN PRECEDING CURRENT,PARTITION BY	Hard	https://datalemur.com/questions/sql-rolling-earnings