Today1. JD 분석2. SQL 코드카타3. SQL Challenge 3회차 과제 풀이 Today I Learned SQL There is a factory website that has several machines each running the same number of processes. Write a solution to find the average time each machine takes to complete a process.1개의 테이블의 같은 컬럼안에 다른 정보가 있을 때의 차이 구하기 SELECT a.machine_id , ROUND(AVG(b.timestamp-a.timestamp),3) processing_time FROM ( SELECT machine_..