SQL Distinct

The DISTINCT keyword allows you to find unique values in a column.

Once a table starts getting a lot of data in it, some columns will contain duplicate values.

For example, many Individuals share first names and surnames. Most of the time this isn't a problem. But sometimes you will want to find out how many unique values there are in a column. To do this you can use the DISTINCT keyword.

SQL statement

SELECT DISTINCT(FirstName) FROM Individual;

Source Table

IndividualIdFirstNameLastNameUserName
1FredFlinstonefreddo
2HomerSimpsonhomey
3HomerBrownnotsofamous
4OzzyOzzbournesabbath
5HomerGainnoplacelike

Result

In this example, using the DISTINCT keyword, all customers with the same first name are treated as one. This results in only one entry for Homer (even though there are three different entries in total).

FirstName
Fred
Homer
Ozzy