SQL Distinct

Example Table

We will use the following table named employees for our examples:

    CREATE TABLE employees (
        employee_id INT PRIMARY KEY,
        employee_name VARCHAR(50),
        department VARCHAR(50),
        salary DECIMAL(10, 2)
    );
    
    INSERT INTO employees (employee_id, employee_name, department, salary) VALUES
    (1, 'John Doe', 'HR', 50000.00),
    (2, 'Jane Smith', 'Finance', 60000.00),
    (3, 'Sam Brown', 'IT', 70000.00),
    (4, 'Nancy White', 'HR', 55000.00),
    (5, 'Mike Green', 'Finance', 65000.00);
    

Using SQL DISTINCT

The SQL DISTINCT keyword is used to return only distinct (different) values.

Selecting Distinct Values from a Column

To select distinct values from a column, use SELECT DISTINCT column_name FROM table_name:

    SELECT DISTINCT department
    FROM employees;
    

Result:

Selecting Distinct Values from Multiple Columns

To select distinct values from multiple columns, use SELECT DISTINCT column1, column2 FROM table_name:

    SELECT DISTINCT department, salary
    FROM employees;
    

Result:

Counting Distinct Values

To count the number of distinct values in a column, use SELECT COUNT(DISTINCT column_name) FROM table_name:

    SELECT COUNT(DISTINCT department) AS unique_departments
    FROM employees;
    

Result: