Alias Names in Sql Server
Introduction#
Here is some of different ways to provide alias names to columns in Sql Server
Using AS
This is ANSI SQL method works in all the RDBMS. Widely used approach.
CREATE TABLE AliasNameDemo (id INT,firstname VARCHAR(20),lastname VARCHAR(20))
INSERT INTO AliasNameDemo
VALUES (1,'MyFirstName','MyLastName')
SELECT FirstName +' '+ LastName As FullName
FROM AliasNameDemo
Using =
This is my preferred approach. Nothing related to performance just a personal choice. It makes the code to look clean. You can see the resulting column names easily instead of scrolling the code if you have a big expression.
CREATE TABLE AliasNameDemo (id INT,firstname VARCHAR(20),lastname VARCHAR(20))
INSERT INTO AliasNameDemo
VALUES (1,'MyFirstName','MyLastName')
SELECT FullName = FirstName +' '+ LastName
FROM AliasNameDemo
Giving alias after Derived table name
This is a weird approach most of the people don’t know this even exist.
CREATE TABLE AliasNameDemo(id INT,firstname VARCHAR(20),lastname VARCHAR(20))
INSERT INTO AliasNameDemo
VALUES (1,'MyFirstName','MyLastName')
SELECT *
FROM (SELECT firstname + ' ' + lastname
FROM AliasNameDemo) a (fullname)
Without using AS
This syntax will be similar to using AS
keyword. Just we don’t have to use AS
keyword
CREATE TABLE AliasNameDemo (id INT,firstname VARCHAR(20),lastname VARCHAR(20))
INSERT INTO AliasNameDemo
VALUES (1,'MyFirstName','MyLastName')
SELECT FirstName +' '+ LastName FullName
FROM AliasNameDemo