SQL aliases are used to give a table, or a column in a table, a temporary name.
Aliases are often used to make column names more readable.
An alias only exists for the duration of that query.
An alias is created with the AS keyword.
SELECT column_name AS alias_name
FROM table_name;
SELECT column_name(s)
FROM table_name AS alias_name;
The following SQL statement creates two aliases, one for the CustomerID column and one for the CustomerName column:
SELECT CustomerID AS ID, CustomerName AS Customer
FROM Customers;
The following SQL statement creates two aliases, one for the CustomerName column and one for the ContactName column. Note: It requires double quotation marks or square brackets if the alias name contains spaces:
SELECT CustomerName AS Customer, ContactName AS [Contact Person]
FROM Customers;
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):
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;
The following SQL statement is the same as above, but without aliases:
SELECT Orders.OrderID, Orders.OrderDate, Customers.CustomerName
FROM Customers, Orders
WHERE Customers.CustomerName='Around the Horn' AND Customers.CustomerID=Orders.CustomerID;
Aliases can be useful when: