SQL: DISTINCT Clause

The DISTINCT clause allows you to remove duplicates from the result set. The DISTINCT clause can only be used with select statements.

The syntax for the DISTINCT clause is:

SELECT DISTINCT columns FROM tables WHERE predicates;

Example #1

Let's take a look at a very simple example.

SELECT DISTINCT city FROM supplier;

This SQL statement would return all unique cities from the supplier table.

Example #2

The DISTINCT clause can be used with more than one field.

For example:

SELECT DISTINCT city, state FROM supplier;

This select statement would return each unique city and state combination. In this case, the distinct applies to each field listed after the DISTINCT keyword.