Occupations in SQL | HackerRank Solution

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

Problem

Pivot the Occupation column in OCCUPATIONS so that each Name is sorted alphabetically and displayed underneath its corresponding Occupation. The output column headers should be Doctor, Professor, Singer, and Actor, respectively.

Note: Print NULL when there are no more names corresponding to an occupation.

Input Format

The OCCUPATIONS table is described as follows:

Column	Type
Name	String
Occupation	String

Occupation will only contain one of the following values: Doctor, Professor, Singer or Actor.

Sample Input

Name	Occupation
Samantha	Doctor
Julia	Actor
Maria	Actor
Ashley	Professor
Ketty	Professor
Christeen	Professor
Jane	Actor
Jenny	Doctor
Priya	Singer

Sample Output

Jenny    Ashley     Meera  Jane
Samantha Christeen  Priya  Julia
NULL     Ketty      NULL   Maria

Explanation

The first column is an alphabetically ordered list of Doctor names.
The second column is an alphabetically ordered list of Professor names.
The third column is an alphabetically ordered list of Singer names.
The fourth column is an alphabetically ordered list of Actor names.
The empty cell data for columns with less than the maximum number of names per occupation (in this case, the Professor and Actor columns) are filled with NULL values.

Solution – Occupations in SQL

MySQL

set @r1=0, @r2=0, @r3=0, @r4=0;
select min(Doctor), min(Professor), min(Singer), min(Actor)
from(select case when Occupation="Doctor" then (@r1:=@r1+1) when Occupation="Professor" then (@r2:=@r2+1) when Occupation="Singer" then (@r3:=@r3+1) when Occupation="Actor" then (@r4:=@r4+1) end as RowNumber,
case when Occupation="Doctor" then Name end as Doctor,
case when Occupation="Professor" then Name end as Professor,
case when Occupation="Singer" then Name end as Singer,
case when Occupation="Actor" then Name end as Actor from OCCUPATIONS order by Name
) Temp group by RowNumber;

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