COMPLEX SQL PRACTICE:-From the doctors table, fetch the details of doctors who work in the same hospital but in different specialty.

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From the doctors table, fetch the details of doctors who work in the same hospital but in different specialty.

Table Name: DOCTORS

Approach: Use self join to solve this problem. Self join is when you join a table to itself.

drop table doctors;
create table doctors
(
id int primary key,
name varchar(50) not null,
speciality varchar(100),
hospital varchar(50),
city varchar(50),
consultation_fee int
);

insert into doctors values(1, ‘Dr. Shashank’, ‘Ayurveda’, ‘Apollo Hospital’, ‘Bangalore’, 2500);
insert into doctors values(2, ‘Dr. Abdul’, ‘Homeopathy’, ‘Fortis Hospital’, ‘Bangalore’, 2000);
insert into doctors values(3, ‘Dr. Shwetha’, ‘Homeopathy’, ‘KMC Hospital’, ‘Manipal’, 1000);
insert into doctors values(4, ‘Dr. Murphy’, ‘Dermatology’, ‘KMC Hospital’, ‘Manipal’, 1500);
insert into doctors values(5, ‘Dr. Farhana’, ‘Physician’, ‘Gleneagles Hospital’, ‘Bangalore’, 1700);
insert into doctors values(6, ‘Dr. Maryam’, ‘Physician’, ‘Gleneagles Hospital’, ‘Bangalore’, 1500);

SOLUTION:

USING SELF JOIN:

select D1.*
from doctors D1 join doctors d2
on D1.ID <> D2.ID
and D1.HOSPITAL = D2.HOSPITAL
AND d1.speciality <> d2.speciality;

OUTPUT WILL BE 3RD AND 4TH ROW

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