As
The AS command is used to rename a column or table with an alias.
An alias only exists for the duration of the query.
Alias for Columns
The following SQL statement creates two aliases, one for the CustomerID column and one for the CustomerName column:
Example
SELECT CustomerID AS ID, CustomerName AS Customer
FROM Customers;The following SQL statement creates two aliases. Notice that it requires double quotation marks or square brackets if the alias name contains spaces:
Example
SELECT CustomerName AS Customer, ContactName AS [Contact Person]
FROM Customers;The following SQL statement creates an alias named "Address" that combine four columns (Address, PostalCode, City and Country):
Example
SELECT CustomerName, Address + ', ' + PostalCode + ' ' + City + ', ' + Country
AS Address
FROM Customers;Note
To get the SQL statement above to work in MySQL use the following:
SELECT CustomerName, CONCAT(Address,', ',PostalCode,', ',City,', ',Country) AS Address
FROM Customers;Alias for Tables
The following SQL statement selects all the orders from the customer with CustomerID=4 (Around the Horn). We use the "Customers" and "Orders" tables, and give them the table aliases of "c" and "o" respectively (Here we use aliases to make the SQL shorter):
Example
SELECT o.OrderID, o.OrderDate, c.CustomerName
FROM Customers AS c, Orders AS o
WHERE c.CustomerName="Around the Horn" AND c.CustomerID=o.CustomerID;