#SQL - Interview Question- SQL to pull unique record after combination of column #SELFJOIN

Hi All,
My name is Ankit Shrivastava and I am Data Engineer.
Today this #vlog is regarding mostly asked #sql #sqlinterviewquestions .

This #vlog is regarding pulling distinct values after combination of columns using SELF JOIN concept.

Problem statement-
Source table contains distance between two cities and contains duplicate data and we need to pull distinct values after combination of columns.
We have table entries such as :-
Distance between Pune and Mumbai is 100KM and same goes for distance between Mumbai and Pune is 100KM. So in our source system we have two records :-

1st record
source_city || destination_city || distance
Pune || Mumbai || 100

2nd record
source_city || destination_city || distance
Mumbai || Pune || 100

Our requirement is to pull only one record out of two records.

Output
source_city || destination_city || distance
Mumbai ||Pune|| 100


Please find the executed SQL code from this video
create table hr.distance (source_city varchar(50),destination_city varchar(50),distance integer);
insert into hr.distance values ('Pune','Mumbai',100);
insert into hr.distance values ('Mumbai','Pune',100);
insert into hr.distance values ('Kolkata','Delhi',200);
insert into hr.distance values ('Delhi','Kolkata',200);
insert into hr.distance values ('Pune','Bangalore',300);
insert into hr.distance values ('Bangalore','Pune',300);

select * from hr.distance ;

#distance #between #city #duplicateenrollment
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