SQL - ALIASES

Aliases can be used with database tables and with database table columns, depending on task you are performing.

SQL column aliases are used to make the output of your SQL queries easy to read and more meaningful:

SELECT Employee, SUM(Hours) As SumHoursPerEmployee FROM EmployeeHours GROUP BY Employee

In the example above we created Alias SumHoursPerEmployee and the result of this SQL query will be the following:

Employee	SumHoursPerEmployee
John Smith	25
Allan Babel	24
Tina Crown	27

Consider the following SQL statement, showing how to use SQL table aliases:

SELECT Emp.Employee FROM EmployeeHours AS Emp

Here is the result of the SQL expression above:

Employee

John Smith

Allan Babel

Tina Crown

 
The SQL table aliases are very useful when you select data from multiple tables.