AS operator

The AS operator in SQL-queries can be used in several different functions.

Specifying names for columns in a query

The AS operator can be used to specify names (aliases) for columns in a table that will be output as the result of a query or used in the query itself:

SELECT
    name AS Student
    FROM students

If the given name contains a space, it must be enclosed in inverted commas:

SELECT
    name AS "Student Name"
    FROM students

Specifying names for tables in a query

The AS operator can be used to specify names (aliases) for tables that are used in a query:

SELECT o.OrderID, o.OrderDate, c.CustomerName
    FROM
        Customers AS c,
        Orders AS o
    WHERE
        c.CustomerName="Tengri" AND c.CustomerID=o.CustomerID;

Here in the query, the aliases c and o for the tables Customers and Orders that are queried are used for brevity.

Specifying a query when creating a table

When creating a table, the AS operator can be used to specify a data query, the result of which will be written to the table being created:

CREATE TABLE films_recent AS
    SELECT * FROM films WHERE date_prod >= '2025-01-01';