INNER JOIN

SQL INNER JOIN Keyword

The INNER JOIN keyword returns only the rows that have matching values in both tables involved in the join. It is commonly used to combine rows from two tables based on a related column.

SQL INNER JOIN Syntax

SELECT column_names
FROM table1
INNER JOIN table2
ON table1.column_name = table2.column_name;

SELECT column_names

FROM table1

INNER JOIN table2

ON table1.column_name = table2.column_name;

SQL INNER JOIN Appointments with Doctors Example

This query displays appointment IDs and the corresponding doctor’s last name by matching doctor_id.

SELECT Appointments.appointment_id, Doctors.last_name
FROM Appointments
INNER JOIN Doctors
ON Appointments.doctor_id = Doctors.doctor_id;

SELECT Appointments.appointment_id, Doctors.last_name

FROM Appointments

INNER JOIN Doctors

ON Appointments.doctor_id = Doctors.doctor_id;

SQL INNER JOIN Appointments with Patients Example

This query displays the appointment ID and patient’s first name for each appointment.

SELECT Appointments.appointment_id, Patients.first_name
FROM Appointments
INNER JOIN Patients
ON Appointments.patient_id = Patients.patient_id;

SELECT Appointments.appointment_id, Patients.first_name

FROM Appointments

INNER JOIN Patients

ON Appointments.patient_id = Patients.patient_id;

SQL INNER JOIN Prescriptions with Appointments and Doctors Example

This query displays prescriptions with related doctor and appointment information.

SELECT Prescriptions.medication_name, Doctors.last_name, Appointments.appointment_date
FROM Prescriptions
INNER JOIN Appointments ON Prescriptions.appointment_id = Appointments.appointment_id
INNER JOIN Doctors ON Appointments.doctor_id = Doctors.doctor_id;

SELECT Prescriptions.medication_name, Doctors.last_name, Appointments.appointment_date

FROM Prescriptions

INNER JOIN Appointments ON Prescriptions.appointment_id = Appointments.appointment_id

INNER JOIN Doctors ON Appointments.doctor_id = Doctors.doctor_id;

SQL INNER JOIN Labs