Create the_report.sql

Author: erjan

hackerrank_sql_practice/the_report.sql

@@ -0,0 +1,37 @@
+/*
+
+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.
+
+*/
+with helper as (
+select id, name, marks, 
+case when  marks >= 0 and marks <=9 then 1
+when marks >=10 and marks <=19 then 2
+when marks >=20 and marks <=29 then 3
+when marks >=30 and marks <=39 then 4
+when marks >=40 and marks <=49 then 5
+when marks >=50 and marks <=59 then 6
+when marks >=60 and marks <=69 then 7
+when marks >=70 and marks <=79 then 8
+when marks >=80 and marks <=89 then 9
+when marks >=90 and marks <=100 then 10
+end as grade
+from students),
+
+bads as(select null as name, grade, marks from helper where grade < 8 order by grade desc, marks),
+
+goods as(select name, grade, marks from helper where grade >= 8 order by grade desc, name),
+
+main as (
+select name, grade, marks from goods
+union all
+select name,  grade, marks from bads)
+
+select * from main order by grade desc,  name, marks