Julia asked her students to create some coding challenges. Write a query to print the hacker_id, name, and the total number of challenges created by each student. Sort your results by the total number of challenges in descending order. If more than one student created the same number of challenges, then sort the result by hacker_id. If more than one student created the same number of challenges and the count is less than the maximum number of challenges created, then exclude those students from the result.
Input Format
The following tables contain challenge data:
Hackers: The hacker_id is the id of the hacker, and name is the name of the hacker.
Challenges: The challenge_id is the id of the challenge, and hacker_id is the id of the student who created the challenge.
Sample Input 0
Sample Output 0
21283 Angela 6
88255 Patrick 5
96196 Lisa 1
Sample Input 1
Sample Output 1
12299 Rose 6
34856 Angela 6
79345 Frank 4
80491 Patrick 3
81041 Lisa 1
Explanation
/*Write a query to print the hacker_id, name, and the total number of challenges created by each student. Sort your results by the total number of challenges in descending order.If more than one student created the same number of challenges, then sort the result byhacker_id. If more than one student created the same number of challenges and the countis less than the maximum number of challenges created, then exclude those students fromthe result.*/WITH temp AS (SELECT h.hacker_id, h.name, COUNT(c.challenge_id) cntFROM Hackers h INNER JOIN Challenges cON h.hacker_id = c.hacker_idGROUP BY h.hacker_id, h.nameORDER BY cnt DESC, h.hacker_id )SELECT*FROM tempWHERE (temp.cnt = (SELECTMAX(cnt) FROM temp)) OR (1= (SELECTCOUNT(cnt) FROM temp u WHERE temp.cnt = u.cnt));-- ORWITH rankings AS (SELECT h.hacker_id, h.name,COUNT(c.challenge_id) AS total_challenges,COUNT(*) OVER(PARTITIONBYCOUNT(c.challenge_id)) AS total_chall_countFROM hackers hLEFT JOIN challenges cON h.hacker_id = c.hacker_idGROUP BY1,2ORDER BYCOUNT(c.challenge_id) DESC, hacker_id )SELECT hacker_id,name, total_challengesFROM rankings WHERE total_challenges = (SELECTMAX(total_challenges) FROM rankings)OR total_chall_count =1
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Hackers Table: Challenges Table:
Hackers Table: Challenges Table:
For Sample Case 0, we can get the following details:
Students 5077and 62743 both created 4 challenges, but the maximum number of challenges created is 6 so these students are excluded from the result.
For Sample Case 1, we can get the following details:
Students 12299 and 34856 both created 6 challenges. Because 6 is the maximum number of challenges created, these students are included in the result.