Naming Results with Aliases

Aliases let you give columns or tables a temporary name inside a query.

For columns, aliases make results easier to read:

SELECT name AS employee_name, salary AS annual_salary
FROM employees

The underlying table still has columns named `name` and `salary`. Only the query result uses `employee_name` and `annual_salary`.

Aliases are especially useful when expressions would otherwise have awkward names:

SELECT salary * 0.10 AS annual_bonus
FROM employees

Tables can have aliases too. You will see this often in joins:

SELECT e.name
FROM employees AS e

Here `e` is a short temporary name for `employees`. It keeps longer queries readable.