What is the issue with my code? HackerRank SQL – 15 Days of Learning SQL

Question :- Julia conducted a 15 days of learning SQL contest. The start date of the contest was March 01, 2016 and the end date was March 15, 2016. (https://www.hackerrank.com/challenges/15-days-of-learning-sql/problem?isFullScreen=true) Write a query to print total number of unique hackers who made at least 1 submission each day (starting on the first day of the contest), and find the hacker_id […]

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