SQL FULL JOIN Statement

What does a SQL FULL JOIN return?

FULL JOIN returns all matching records from both tables whether the other table matches or not.
Be aware that a FULL JOIN can potentially return very large datasets.
These two: FULL JOIN and FULL OUTER JOIN are the same.

The SQL FULL JOIN syntax

The general syntax is:

SELECT column-names
  FROM table-name1 FULL JOIN table-name2 
    ON column-name1 = column-name2
 WHERE condition

The general FULL OUTER JOIN syntax is:

    SELECT column-names
  FROM table-name1 FULL OUTER JOIN table-name2 
    ON column-name1 = column-name2
 WHERE condition

SUPPLIER
Id
CompanyName
ContactName
City
Country
Phone
Fax

CUSTOMER
Id
FirstName
LastName
City
Country
Phone

SQL FULL JOIN Examples

Problem: Match all customers
and suppliers by country

SELECT C.FirstName, C.LastName, C.Country AS CustomerCountry, 
       S.Country AS SupplierCountry, S.CompanyName
  FROM Customer C FULL JOIN Supplier S 
    ON C.Country = S.Country
 ORDER BY C.Country, S.Country

This returns suppliers that have no customers in their country,
and customers that have no suppliers in their country,
and customers and suppliers that are from the same country.

Result: 195 records

FirstName	LastName	CustomerCountry	SupplierCountry	CompanyName
NULL	NULL	NULL	Australia	Pavlova, Ltd.
NULL	NULL	NULL	Australia	G'day, Mate
NULL	NULL	NULL	Japan	Tokyo Traders
NULL	NULL	NULL	Japan	Mayumi's
NULL	NULL	NULL	Netherlands	Zaanse Snoepfabriek
NULL	NULL	NULL	Singapore	Leka Trading
Patricio	Simpson	Argentina	NULL	NULL
Yvonne	Moncada	Argentina	NULL	NULL
Sergio	Gutiérrez	Argentina	NULL	NULL
Georg	Pipps	Austria	NULL	NULL
Roland	Mendel	Austria	NULL	NULL
Pascale	Cartrain	Belgium	NULL	NULL
Catherine	Dewey	Belgium	NULL	NULL
Bernardo	Batista	Brazil	Brazil	Refrescos Americanas LTDA
Lúcia	Carvalho	Brazil	Brazil	Refrescos Americanas LTDA
Janete	Limeira	Brazil	Brazil	Refrescos Americanas LTDA
Aria	Cruz	Brazil	Brazil	Refrescos Americanas LTDA
André	Fonseca	Brazil	Brazil	Refrescos Americanas LTDA
Mario	Pontes	Brazil	Brazil	Refrescos Americanas LTDA
Pedro	Afonso	Brazil	Brazil	Refrescos Americanas LTDA
Paula	Parente	Brazil	Brazil	Refrescos Americanas LTDA
Anabela	Domingues	Brazil	Brazil	Refrescos Americanas LTDA
Elizabeth	Lincoln	Canada	Canada	Ma Maison
Elizabeth	Lincoln	Canada	Canada	Forêts d'érables
Yoshi	Tannamuri	Canada	Canada	Ma Maison
Yoshi	Tannamuri	Canada	Canada	Forêts d'érables
Jean	Fresnière	Canada	Canada	Ma Maison