pbj0812의 코딩 일기

0. 목표 - rolling retention 계산 1. 실습 1) 데이터 만들기 - 링크 2) 쿼리 작성 (1) 각 id 별 첫 번째 접속일과 마지막 접속일 연산 WITH summary AS ( SELECT id, MIN(dated) AS first_login, MAX(dated) AS last_login FROM sql_test.classic_retention GROUP BY 1 ORDER BY 1 ), (2) 달력 생성 Calendar AS ( SELECT CONCAT(y, '0101') + INTERVAL tt*1000 + a*100 + b*10 + c DAY AS dt FROM (SELECT 0 AS tt UNION ALL SELECT 1 UNION ALL SELECT 2 UNION ALL SE..