[해커랭크] MySQL JOIN - New Companies

New Companies | HackerRank Find total number of employees. www.hackerrank.com 이번 문제는 JOIN과 계산함수를 활용하는 문제입니다. Amber's conglomerate corporation just acquired some new companies. Each of the companies follows this hierarchy: 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, ..

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