The Report
Problem Statement : You are given two tables: Students and Grades. Students contain three columns ID, Name and Marks.
Sample Input data of Students table:
Grades contains the following data:
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.
Expected output :
Maria 10 99
Jane 9 81
Julia 9 88
Scarlet 8 78
NULL 7 63
NULL 7 68
Solution :
For this challenge, we must:
Use an if condition to assign NULL for lower grades.
Assign grades using the WHERE and BETWEEN clause so that records where Marks between MIN_Mark and Max_Mark joins and return a joined table.
Query :
SELECT IF(GRADE < 8, NULL, NAME), GRADE, MARKS
FROM STUDENTS JOIN GRADES
WHERE MARKS BETWEEN MIN_MARK AND MAX_MARK
ORDER BY GRADE DESC, NAME;
Output:
Hope you learn something !!!
If you have any questions let me know in the comment section.