47

Challenge 47 - Top competitors

Julia just finished conducting a coding contest, and she needs your help assembling the leaderboard! Write a query to print the respective hacker_id and name of hackers who achieved full scores for more than one challenge. Order your output in descending order by the total number of challenges in which the hacker earned a full score. If more than one hacker received full scores in same number of challenges, then sort them by ascending hacker_id.

The Hackers table is described as follows:

Column	Type
hacker_id	Integer
name	String

The hacker_id is the id of the hacker, and name is the name of the hacker.

The Difficulty table is described as follows:

Column	Type
difficulty_level	Integer
score	Integer

The difficulty_level is the level of difficulty of the challenge, and score is the maximum score that can be achieved for a challenge at that difficulty level.

The Challenges table is described as follows:

Column	Type
challenge_id	Integer
hacker_id	Integer
difficulty_level	Integer

The challenge_id is the id of the challenge, the hacker_id is the id of the hacker who created the challenge, and difficulty_level is the level of difficulty of the challenge.

The Submissions table is described as follows:

Column	Type
submission_id	Integer
hacker_id	Integer
challenge_id	Integer
score	Integer

The submission_id is the id of the submission, hacker_id is the id of the hacker who made the submission, challenge_id is the id of the challenge that the submission belongs to, and score is the score of the submission.

Solutions

• Microsoft SQL Server