Aliasing:

SQL aliases are used to give a table, or a column in a table, a temporary name. These are often used to make column names more readable. It only exists for the duration of that query which is created with the AS keyword.

Alias for Columns Examples:

We can assign new column name  to existing column name.

Example, CustomerID  will be as ID and CustomerName  will be as Customer

SELECT CustomerID AS ID, CustomerName AS Customer
FROM Customers;

Alias for Tables Example:

Aliases are used to address database tables with a shorter or more meaningful name within an SQL query. The basic syntax of a table alias is as follows.

SELECT column1, column2....
FROM table_name AS alias_name

Example: 

SELECT C.ID, C.NAME, C.AGE, O.AMOUNT 
FROM CUSTOMERS AS C, ORDERS AS O
WHERE  C.ID = O.CUSTOMER_ID;

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