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Self Join Syntax

SELECT
column_name(s)
FROM
table1 T1, table1 T2 WHERE
condition
;

T1 and T2 are different table aliases for the same table.

Demo Database

Below is a selection from the "Customers" table:

CustomerID	CustomerName	ContactName	Address	City	PostalCode	Country
1	Alfreds Futterkiste	Maria Anders	Obere Str. 57	Berlin	12209	Germany
2	Ana Trujillo Emparedados y helados	Ana Trujillo	Avda. de la ConstituciÃ³n 2222	MÃ©xico D.F.	05021	Mexico
3	Antonio Moreno TaquerÃa	Antonio Moreno	Mataderos 2312	MÃ©xico D.F.	05023	Mexico

SQL Self Join Example

The following SQL statement matches customers that are from the same city:

Example

  SELECT A.CustomerName AS CustomerName1, B.CustomerName AS CustomerName2,
  A.City
FROM Customers A, Customers B
WHERE A.CustomerID <> B.CustomerID

  AND A.City = B.City
ORDER BY A.City;