Using SQL Distinct to Exclude Duplicates

Syntax of SQL SELECT DISTINCT

SELECT DISTINCT column1, column2, ...
FROM table_name;

Examples using a demo database

The Developers table

Selecting all values from one column

SELECT City FROM Developers;

Selecting only distinct values from one column

SELECT DISTINCT City FROM Developers;

Counting distinct values

SELECT COUNT(DISTINCT City) FROM Developers;

Note: this example will not work in Microsoft Edge and Firefox, as they use Microsoft Access which doesn't support COUNT(DISTINCT column_name).

In MS Access

SELECT Count(*) AS DistinctCities
FROM (SELECT DISTINCT City FROM Developers);