Content

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1. Description of SQL
2. StrataScratch Solutions
3. Leetcode Solutions
4. Hackerrank Solutions
5. DataLemur Solutions

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SQL

Structured Query Language(SQL) is special purpose programming language which is designed for managing relational database. SQL is the one of the basis for relational database. SQL provides various commands and classified as :

• Data Definition Language(DDL):CREATE, DROP, TRUNCATE, ALTER
• Data Manipulation Language(DML):SELECT, INSERT,UPDATE, DELETE
• Data Control Language(DCL): GRANT, REVOKE
• Transaction Control Language(TCL):COMMIT, ROLLBACK, SAVEPOINT

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The below are my solutions to the various queries and challenges

StrataScratch

ID	QUESTION	ANSWER	IMAGE
1	Salaries Differences	Solution	Output
2	Finding Updated Records	Solution	Output
3	Unique Users Per Client Per Month	Solution	Output
4	Bikes Last Used	Solution	Output
5	Reviews of Hotel Arena	Solution	Output
6	Count the number of movies that Abigail Breslin nominated for oscar	Solution	Output
7	Popularity of Hack	Solution	Output
8	Lyft Driver Wages	Solution	Output
9	Find how many times each artist appeared on the Spotify ranking list	Solution	Output
10	Find the base pay for Police Captains	Solution	Output
11	Find libraries who haven't provided the email address in circulation year 2016 but their notice preference definition is set to email	Solution	Output
12	Average Salaries	Solution	Output
13	Customer Details	Solution	Output
14	Number of Workers by Department Starting in April or Later	Solution	Output
15	Admin Department Employees Beginning in April or Later	Solution	Output
16	Churro Activity Date	Solution	Output
17	Find the most profitable company in the financial sector of the entire world along with its continent	Solution	Output
18	Count the number of user events performed by MacBookPro users	Solution	Output
19	Number Of Bathrooms And Bedrooms	Solution	Output
20	Number of Shipments Per Month	Solution	Output
21	Order Details	Solution	Output
22	Find all posts which were reacted to with a heart	Solution	Output
23	Most Lucrative Products	Solution	Output
24	Activity Rank	Solution	Output
25	New Products	Solution	Output
26	Number Of Units Per Nationality	Solution	Output
27	Ranking Most Active Guests	Solution	Output
28	Find the top 10 ranked songs in 2010	Solution	Output
29	Top Cool Votes	Solution	Output
30	Find matching hosts and guests in a way that they are both of the same gender and nationality	Solution	Output
31	Highest Salary In Department	Solution	Output
32	Number of violations	Solution	Output
33	Top Ranked Songs	Solution	Output
34	Find all wineries which produce wines by possessing aromas of plum, cherry, rose, or hazelnut	Solution	Output
35	Highest Cost Orders	Solution	Output
36	Second Highest Salary	Solution	Output
37	Customer Revenue In March	Solution	Output
38	Highest Target Under Manager	Solution	Output
39	Employee and Manager Salaries	Solution	Output
40	Top Businesses With Most Reviews	Solution	Output
41	Workers with Highest Solution	Solution	Output
42	Spam Posts	Solution	Output
43	Income By Title AND Gender	Solution	Output
44	Apple Products	Solution	Output
45	Premium VS Freemium	Solution	Output
46	Survivors And NON-Survivors	Solution	Output
47	Classify Business Types	Solution	Output
48	Share Of Active Users	Solution	Output
49	Flags Per Video	Solution	Output
50	User With Most Approved Flags	Solution	Output
51	Find The Rate of Processed Ticket For Each Type	Solution	Output
52	Top Five States With Five Star Business	Solution	Output
53	City With Most Amenities	Solution	Output

Leetcode

ID	QUESTION	ANSWER
1	Recyclable and Low Fat Products	Solution
2	Find Customer Referee	Solution
3	Big Countries	Solution
4	Article Views I	Solution
5	Invalid Tweets	Solution
6	Replace Employee ID With The Unique Identifier	Solution
7	Product Sales Analysis I	Solution
8	Customer Who Visited but Did Not Make Any Transactions	Solution
9	Rising Temperature	Solution
10	Employee Bonus	Solution
11	Not Boring Movies	Solution
12	Project Employees I	Solution
13	Queries Quality and Percentage	Solution
14	Classes More Than 5 Students	Solution
15	Find Followers Count	Solution
16	Biggest Single Number	Solution
17	Customers Who Bought All Products	Solution
18	Fix Names in a Table	Solution
19	Patients With a Condition	Solution
20	Average Time of Process per Machine	Solution
21	Employees Whose Manager Left the Company	Solution
22	Second Highest Salary	Solution
23	Count Salary Categories	Solution
24	Product Sales Analysis III	Solution
25	Department Top Three Salaries	Solution
26	Group Sold Products By Date	Solution
27	List The Products Ordered In a Period	Solution
28	Students and Examinations	Solution
29	User Activity for the Past 30 Days I	Solution
30	Number Of Unique Subjects Taught By Each Teacher	Solution
31	Find Users With Valid Email	Solution
32	Managers With Five Atleast Direct Reports	Solution
33	Confirmation Rate	Solution
34	Delete Duplicate Emails	Solution
35	Percentage Of Users Attended a Contest	Solution
36	Monthly Transactions I	Solution
37	Average Selling Price	Solution
38	Triangle Judgement	Solution
39	Primary Department for Each Employee	Solution
40	Exchange Seats	Solution
41	Consecutive Numbers	Solution
42	The Number of Employee Which Report to Each Employee	Solution
43	Friend Request II	Solution
44	Movie Rating	Solution

HackerRank

ID	QUESTION	ANSWER
1	Select All	Solution
2	Revising the Select Query I	Solution
3	Revising the Select Query II	Solution
4	Select By ID	Solution
5	Japanese Cities' Attributes	Solution
6	Japanese Cities' Names	Solution
7	Weather Observation Station 1	Solution
8	Weather Observation Station 3	Solution
9	Weather Observation Station 4	Solution
10	Weather Observation Station 5	Solution
11	Weather Observation Station 6	Solution
12	Weather Observation Station 7	Solution
13	Weather Observation Station 8	Solution
14	Weather Observation Station 9	Solution
15	Weather Observation Station 10	Solution
16	Weather Observation Station 11	Solution
17	Weather Observation Station 12	Solution
18	Higher Than 75 Marks	Solution
19	Employee Names	Solution
20	Employee Salaries	Solution
21	Placements	Solution
22	Binary Tree Nodes	Solution
23	New Companies	Solution
24	Weather Observation Station 18	Solution
25	Weather Observation Station 19	Solution

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DataLemur

ID	QUESTION	ANSWER	IMAGE
1	Data Science Skills	Solution	Output
2	Page With No Likes	Solution	Output
3	Unfinished Parts	Solution	Output
4	Laptop vs. Mobile Viewership	Solution	Output
5	Cities With Completed Trades	Solution	Output
6	Teams Power Users	Solution	Output
7	Average Review Ratings	Solution	Output
8	Cards Issued Difference	Solution	Output
9	Compressed Mean	Solution	Output
10	Pharmacy Analytics (Part 1)	Solution	Output
11	Pharmacy Analytics (Part 2)	Solution	Output
12	App Click-through Rate (CTR)]	Solution	Output
13	Duplicate Job Listings	Solution	Output
14	Average Post Hiatus (Part 1)	Solution	Output
15	Well Paid Employees	Solution	Output
16	Top Five Artists	Solution	Output
17	Second Highest Salary	Solution	Output
18	Top Three Salaries	Solution	Output
19	Highest Grossing Items	Solution	Output
20	SuperCloud Customer	Solution	Output
21	Sending Vs Opening Snaps	Solution	Output
22	Swapped Food Delivery	Solution	Output
23	Histogram of Users and Purchases	Solution	Output
24	Advertiser Status	Solution	Output
25	Repeated Transactions	Solution	Output
26	Who Made Quotas	Solution	Output
27	IBM DB2 Product Analysis	Solution	Output