찌니의 프로그래밍 삼매경

https://leetcode.com/problems/second-highest-salary/ Second Highest Salary - LeetCode Level up your coding skills and quickly land a job. This is the best place to expand your knowledge and get prepared for your next interview. leetcode.com salary가 2번째로 높은친구 뽑기 예외조건은 row가 1개일경우 null 출력 MYSQL Oracle

https://leetcode.com/problems/rising-temperature/ Rising Temperature - LeetCode Level up your coding skills and quickly land a job. This is the best place to expand your knowledge and get prepared for your next interview. leetcode.com 어제보다 온도가 높은 id출력 Oracle Mysql

https://leetcode.com/problems/reformat-department-table/ Reformat Department Table - LeetCode Level up your coding skills and quickly land a job. This is the best place to expand your knowledge and get prepared for your next interview. leetcode.com 각 부서의 월별 수익현황 출력 1-3월만 존재 4-12월 내역은 null 더 좋은방법이 있는지는 추후에 찾아보는걸로..

https://leetcode.com/problems/customers-who-never-order/ Customers Who Never Order - LeetCode Level up your coding skills and quickly land a job. This is the best place to expand your knowledge and get prepared for your next interview. leetcode.com 주문안한 고객 찾아내기 not exists를 이용하며 풀이했다 심플!

https://leetcode.com/problems/duplicate-emails/ Duplicate Emails - LeetCode Level up your coding skills and quickly land a job. This is the best place to expand your knowledge and get prepared for your next interview. leetcode.com LeetCode SQL문제풀이 시작 문제는 심플하다 중복된 이메일이 1개 초과인 이메일을 뽑아내면된다. select email from Person group by email having count(email) > 1 심플!!