How to join 3 or more tables in SQL

In a database, information is typically separated into different tables. The JOIN (or INNER JOIN) statement enables us to combine the columns we require into a single table. The syntax of joining 3 or more tables is the same as joining 2 tables:​

JOIN, INNER JOIN and , can be used to join tables. However, if a , is used, then the WHERE clause needs to be used instead of the ON clause.

1. Simple Join

First, all the tables are joined using the JOIN keyword, then the WHERE clause is used:

FROM Employee e JOIN Salary s JOIN Department d
        WHERE e.ID = s.Emp_ID AND e.Dep_ID = d.ID

2. Nested Join

The nested JOIN statement is used with the ON keyword:

SELECT e.ID, e.Name, s.Salary, d.Name
FROM (Employee e JOIN Salary s ON e.ID = s.Emp_ID)
  JOIN Department d ON e.Dep_ID = d.ID