PostgreSQL SELECT DISTINCT

The SELECT DISTINCT Statement

The SELECT DISTINCT statement is used to return only distinct (different) values.

Inside a table, a column often contains many duplicate values and sometimes you only want to list the different (distinct) values.

Example

Select only the DISTINCT values from the country column in the customers table:

SELECT DISTINCT country FROM customers;

Even though the customers table has 91 records, it only has 21 different countries, and that is what you get as a result when executing the SELECT DISTINCT statement above

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SELECT COUNT(DISTINCT)

We can also use the DISTINCT keyword in combination with the COUNT statement, which in the example below will return the number of different countries there are in the customers table.

Example

Return the number of different countries there are in the customers table:

SELECT COUNT(DISTINCT country) FROM customers;

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PostgreSQL Exercises

Test Yourself With Exercises

Exercise:

Write the correct SQL statement to select the column country from the table customers.

But return only different values: country FROM customers;