3 table join query processing code example
Example: 3 joins in sql
SELECT e.FIRST_NAME , -- coming from EMPLOYEES table
d.DEPARTMENT_NAME ,-- coming from DEPARTMENTS table
l.CITY , -- coming from LOCATIONS table
c.COUNTRY_NAME , -- coming from COUNTRIES table
r.REGION_NAME -- coming from REGIONS table
FROM EMPLOYEES e
INNER JOIN DEPARTMENTS d on e.DEPARTMENT_ID = d.DEPARTMENT_ID
INNER JOIN LOCATIONS l on l.LOCATION_ID = d.LOCATION_ID
INNER JOIN COUNTRIES c on l.COUNTRY_ID = c.COUNTRY_ID
INNER JOIN REGIONS r on c.REGION_ID = r.REGION_ID ;