SQL INNER JOIN Keyword

The INNER JOIN keyword return rows when there is at least one match in both tables.

SQL INNER JOIN Syntax

SELECT column_name(s) FROM table_name1 INNER JOIN table_name2 ON table_name1.column_name=table_name2.column_name

SQL INNER JOIN Example

The "Persons" table:

Id	LastName	FirstName	Address	City
1	Navis	Anto	Madras	TVL
2	Ji	Bala	Bombay	TVL
3	Christopher	Franklin	America	KK

The "Orders" table:

Id	OrderNo	Id
1	77895	3
2	44678	3
3	22456	1
4	24562	1
5	34764	15

Now we want to list all the persons with any orders.

We use the following SELECT statement:

SELECT Persons.LastName, Persons.FirstName, Orders.OrderNo FROM Persons INNER JOIN Orders ON Persons.Id=Orders.Id ORDER BY Persons.LastName

The result-set will look like this:

LastName	FirstName	OrderNo
Navis	Anto	22456
Navis	Anto	24562
Christopher	Franklin	77895
Christopher	Franklin	44678

The INNER JOIN keyword return rows when there is at least one match in both tables. If there are rows in "Persons" that do not have matches in "Orders", those rows will NOT be listed.