SQL - Select Distinct Records

A column in the database table may contain duplicate values. The SELECT DISTINCT statement is used to retrieve unique values of a column or combination of one or more columns.

Syntax:

SELECT DISTINCT column_name1, column_name2,...
FROM table_name
[WHERE Condition];

For the demo purpose, we will use the following Employee table in all examples.

The following query returns unique records from the Employee table.

SELECT DISTINCT * FROM Employee;

The above query returns all the unique records even if at least one column has a unique value.

The following query retrieves the unique FirstName values.

SELECT DISTINCT FirstName FROM Employee;

The following query retrieves the unique combination of FirstName and LastName values.

SELECT DISTINCT FirstName, LastName FROM Employee;

The following counts the unique EmpId.

SELECT count(DISTINCT EmpId) FROM Employee;