SQL Alias

SQL Aliases are defined for columns and tables. Basically aliases is created to make the column selected more readable.


For Example: To select the first name of all the students, the query would be like:


Aliases for columns:


SELECT first_name AS Name FROM student_details;

or

SELECT first_name Name FROM student_details;


In the above query, the column first_name is given a alias as 'name'. So when the result is displayed the column name appears as 'Name' instead of 'first_name'.


Output:


Name

-------------

Rahul Sharma

Anjali Bhagwat

Stephen Fleming

Shekar Gowda

Priya Chandra






Aliases for tables:


SELECT s.first_name FROM student_details s;


In the above query, alias 's' is defined for the table student_details and the column first_name is selected from the table.


Aliases is more useful when


There are more than one tables involved in a query,

Functions are used in the query,

The column names are big or not readable,

More than one columns are combined together