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SQL > Basic Join > Contest Leaderboard Contest Leaderboard | HackerRank Generate the contest leaderboard. www.hackerrank.com The total score of a hacker is the sum of their maximum scores for all of the challenges. Write a query to print the hacker_id, name, and total score of the hackers ordered by the descending score. If more than one hacker achieved the same total score, then sort the result..

SQL > Advanced Join > Symmetric Pairs Symmetric Pairs | HackerRank Write a query to output all symmetric pairs in ascending order by the value of X. www.hackerrank.com Two pairs (X1, Y1) and (X2, Y2) are said to be symmetric pairs if X1 = Y2 and X2 = Y1. Write a query to output all such symmetric pairs in ascending order by the value of X. List the rows such that X1 ≤ Y1. 빨간 글씨는 내가 문제를 풀 때 중요하다고..

SQL > Advanced Select > New Companies New Companies | HackerRank Find total number of employees. www.hackerrank.com Given the table schemas below, write a query to print the company_code, founder name, total number of lead managers, total number of senior managers, total number of managers, and total number of employees. Order your output by ascending company_code. Note: The tables may contain d..

SQL > Advanced Select > Binary Tree Nodes Write a query to find the node type of Binary Tree ordered by the value of the node. Output one of the following for each node: Root: If node is root node. Leaf: If node is leaf node. Inner: If node is neither root nor leaf node. 빨간 글씨는 내가 문제를 풀 때 중요하다고 생각한 부분이다. SELECT N, CASE WHEN P IS NULL THEN 'Root' ELSE CASE WHEN N IN (SELECT P FROM BST) THEN 'Inne..

SQL > Aggregation > Weather Observation Station 19 Weather Observation Station 19 | HackerRank Query the Euclidean Distance between two points and round to 4 decimal digits. www.hackerrank.com Consider P1(a, c) and P2(b, d) to be two points on a 2D plane where (a,b) are the respective minimum and maximum values of Northern Latitude (LAT_N) and (c, d) are the respective minimum and maximum values..

SQL > Advanced Select > The PADS The PADS | HackerRank Query the name and abbreviated occupation for each person in OCCUPATIONS. www.hackerrank.com 1. Query an alphabetically ordered list of all names in OCCUPATIONS, immediately followed by the first letter of each profession as a parenthetical (i.e.: enclosed in parentheses). For example: AnActorName(A), ADoctorName(D), AProfessorName(P), and A..