The Report in SQL | HackerRank Solution

Hello coders, today we are going to solve The Report HackerRank Solution in SQL.

Problem

You are given two tables: Students and Grades. Students contains three columns ID, Name and Marks.

Column	Type
ID	Integer
Name	String
Marks	Integer

Grades contains the following data:

Grade	Min_Mark	Max_Mark
1	0	9
2	10	19
3	20	29
4	30	39
5	40	49
6	50	59
7	60	69
8	70	79
9	80	89
10	90	99

Ketty gives Eve a task to generate a report containing three columns: Name, Grade and Mark. Ketty doesn’t want the NAMES of those students who received a grade lower than 8. The report must be in descending order by grade — i.e. higher grades are entered first. If there is more than one student with the same grade (8-10) assigned to them, order those particular students by their name alphabetically. Finally, if the grade is lower than 8, use “NULL” as their name and list them by their grades in descending order. If there is more than one student with the same grade (1-7) assigned to them, order those particular students by their marks in ascending order.

Write a query to help Eve.

Sample Input

Id	Name	Marks
1	Julia	88
2	Samantha	68
3	Maria	99
4	Scarlet	78
5	Ashley	63
6	Jane	81

Sample Output

Maria 10 99
Jane 9 81
Julia 9 88 
Scarlet 8 78
NULL 7 63
NULL 7 68

Note

Print “NULL”  as the name if the grade is less than 8.

Explanation

Consider the following table with the grades assigned to the students:

Id	Name	Marks	Grade
1	Julia	88	9
2	Samantha	68	7
3	Maria	99	10
4	Scarlet	78	8
5	Ashley	63	7
6	Jane	81	9

So, the following students got 8, 9 or 10 grades:

• Maria (grade 10)
• Jane (grade 9)
• Julia (grade 9)
• Scarlet (grade 8)

Solution – The Report in SQL

MySQL

SELECT CASE
    WHEN G.grade > 7 THEN S.name
    ELSE NULL
    end AS names,
    G.grade,
    S.marks
FROM   students S
    JOIN grades G
    ON S.marks BETWEEN G.min_mark AND G.max_mark
ORDER  BY G.grade DESC,
    names ASC,
    S.marks ASC;

Disclaimer: The above Problem (The Report) is generated by Hacker Rank but the Solution is Provided by CodingBroz. This tutorial is only for Educational and Learning Purpose.