SQL Tutorial

SQL HOME SQL Intro SQL Syntax SQL Select SQL Select Distinct SQL WHERE SQL Order By SQL AND SQL OR SQL NOT SQL Insert Into SQL Null Values SQL Update SQL Delete SQL Select Top SQL Min and Max SQL Count SQL Sum SQL Avg SQL Like SQL Wildcards SQL In SQL Between SQL Aliases SQL Joins SQL Inner Join SQL Left Join SQL Right Join SQL Full Join SQL Self Join SQL Union SQL Group By SQL Having SQL Exists SQL Any, All SQL Select Into SQL Insert Into Select SQL Case SQL Null Functions SQL Stored Procedures SQL Comments SQL Operators

SQL Database

SQL Create DB SQL Drop DB SQL Backup DB SQL Create Table SQL Drop Table SQL Alter Table SQL Constraints SQL Not Null SQL Unique SQL Primary Key SQL Foreign Key SQL Check SQL Default SQL Index SQL Auto Increment SQL Dates SQL Views SQL Injection SQL Hosting SQL Data Types

SQL References

SQL Keywords MySQL Functions SQL Server Functions MS Access Functions SQL Quick Ref

SQL Examples

SQL Examples SQL Editor SQL Quiz SQL Exercises SQL Bootcamp SQL Certificate

SQL. Lessons for beginners


SQL Aliases

SQL Aliases

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.

Alias Column Syntax

SELECT column_name AS alias_name
FROM table_name;

Alias Table Syntax

SELECT column_name(s)
FROM table_name AS alias_name;

Demo Database

In this tutorial we will use the well-known Northwind sample database.

Below is a selection from the "Customers" table:

CustomerID CustomerName ContactName Address City PostalCode Country
2 Ana Trujillo Emparedados y helados Ana Trujillo Avda. de la Constitución 2222 México D.F. 05021 Mexico
3 Antonio Moreno Taquería Antonio Moreno Mataderos 2312 México D.F. 05023 Mexico
4 Around the Horn Thomas Hardy 120 Hanover Sq. London WA1 1DP UK

And a selection from the "Orders" table:

OrderID CustomerID EmployeeID OrderDate ShipperID
10354 58 8 1996-11-14 3
10355 4 6 1996-11-15 1
10356 86 6 1996-11-18 2

Alias for Columns Examples

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;
Try it Yourself »

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;
Try it Yourself »

The following SQL statement creates an alias named "Address" that combine four columns (Address, PostalCode, City and Country):


SELECT CustomerName, Address + ', ' + PostalCode + ' ' + City + ', ' + Country AS Address
FROM Customers;
Try it Yourself »

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;

Note: To get the SQL statement above to work in Oracle use the following:

SELECT CustomerName, (Address || ', ' || PostalCode || ' ' || City || ', ' || Country) AS Address
FROM Customers;

Alias for Tables Example

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;
Try it Yourself »

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;
Try it Yourself »

Aliases can be useful when:

  • There are more than one table involved in a query
  • Functions are used in the query
  • Column names are big or not very readable
  • Two or more columns are combined together

Test Yourself With Exercises


When displaying the Customers table, make an ALIAS of the PostalCode column, the column should be called Pno instead.

SELECT CustomerName,
FROM Customers;