SQL - DISTINCT

The DISTINCT clause is used together with the SELECT keyword, to return a dataset with unique entries for certain database table column.

We will use our Customers database table to illustrate the usage of DISTINCT.

FirstName	LastName	Email	DOB	Phone
John	Smith	John.Smith@yahoo.com	2/4/1968	626 222-2222
Steven	Goldfish	goldfish@fishhere.net	4/4/1974	323 455-4545
Paula	Brown	pb@herowndomain.org	5/24/1978	416 323-3232
James	Smith	jim@supergig.co.uk	20/10/1980	416 323-8888

For example if we want to select all distinct surnames from our Customers table, we will use the following DISTINCT statement:

SELECT DISTINCT LastName FROM Customers

The result of the DISTINCT expression above will look like this:

LastName

Smith

Goldfish

Brown