Leetcode sql

Is LeetCode built for data science interview preparation? LeetCode is the de facto and primary educational platform for people preparing for software development under works software engineer SWE interviews, as well as for people looking to upskill their software development skills in general. According to their site, in two short years after launch, they reached over 1 million users on their platform. LeetCode has leetcode sql the coding questions you could want to prepare for your software engineering interviews and includes over questions that test for different technical concepts like data structures and search algorithms, leetcode sql.

Write a SQL query for a report that provides the following information for each person in the Person table, regardless if there is an address for each of those people:. For example, given the above Employee table, the query should return as the second highest salary. If there is no second highest salary, then the query should return null. If there is no nth highest salary, then the query should return null. Write a SQL query to rank scores.

Leetcode sql

Leetcode has undoubtedly excelled in preparing software engineers for coding interviews, and now SQLPad brings that same focus to data science and data analytics candidates prepping for SQL coding interviews. At last, data scientists and data analysts can enjoy a comprehensive SQL coding interview preparation journey designed just for them. To ensure targeted practice, we've compiled a collection of essential company and industry-specific SQL coding questions from leading tech giants like Amazon , Google , Airbnb , and TikTok. The questions may frustrates you, make your underestimate yourself, especially if you just started. You can jump right into the coding environment after learning the concepts. Join over 50, happy customers, including many from the world's best companies and universities. Hi Leon, I hope you're doing well. I wanted to reach out and say thanks for your interview prep—it really helped me land a position at Amazon. It's been a fulfilling experience! Data Engineer at Amazon. I got a job offer at Amazon as a Data Engineer! I worked with Leon and he was super helpful to me at every stage of the process of getting a new role! He helped me strategize a study plan for technical interviews, shared knowledge of what different data roles are like and which one I would like, and evaluate and negotiate what is important to me in the offer! The best thing that I learned working with Leon is how to spend my time effectively in the interview process.

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I resolved all the database questions on Leetcode. I provided the answers as well as explanations in this blog, as a way to consolidate the SQL knowledge. A typical problem of self join. Join the table with itself, for each row compare the salaries of employee and manager. Note: Subquery returned more than 1 value.

This collection of SQL questions is carefully curated to help enhance SQL skills and prepare for technical interviews. Whether you are a beginner looking to dive into SQL or an experienced professional aiming to sharpen your problem-solving abilities, this repository has got you covered. The repository is organized into folders, each corresponding to a different SQL topic or category. Within each folder, you'll find the SQL questions, their descriptions, and accompanying solutions. The solutions are provided in MySQL. Feel free to explore the repository and choose the topics or questions that align with your learning goals. Solve the questions, analyze the solutions, and challenge yourself to optimize the code further. It's all about building your SQL skills and gaining confidence in your abilities. Contributions to this repository are welcome! If you have a new SQL question, an improved solution, or a suggestion to enhance the repository, feel free to submit a pull request.

Leetcode sql

Understand Basics:. Learn what SQL is and its purpose in managing relational databases. Understand basic database concepts like tables, rows, columns, and relationships. Learn SQL Syntax :. Practice creating databases, tables, and inserting data.

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For the above table, your SQL query should return:. LastName , a. It's very easy to retain the unique emails with the smallest ids. FROM Orders. With sqlpad. FROM Person p. Product table:. There are 80 plus SQL challenges ranging from easy to hard. The practice to communicate project work to peers is another highlight to help me earn higher score. First select maxmium salary in each department with corresponding Id. Depending on the project's difficulty, it could that everything from data cleaning and analysis to statistics, machine learning, model building and deploying, and data visualization. Write a SQL query to find all customers who never order anything. In this case, you just need to simply count the total accepted requests no matter whether they are in the original requests , and divide it by the number of requests to get the acceptance rate. Write an SQL query that reports the number of posts reported yesterday for each report reason.

Solved SQL questions in the second round. Aim to organize Multiple solutions and thoughts for each question, compare and find the optimal ones. It contains an auto-generated table of all solutions with links to the solution, problem, and BigO time and memory analysis.

Looking forward to your mentorship program. FROM customer. Project table:. However, note the question require to delete the duplicate emails, so Delete clause is needed. The ability to also discuss and ask data science questions about each interview question and your code with the StrataScratch community is another big benefit. This is apparent from having only database type questions. Video is more easily consumable than text but much more time consuming to create. Shoutout to Leon Wei from instamentor. For the sample data above, the result is:. Salary ;. JOIN Activity t2.