Aliasing in SQL

Giving a table or column a temporary name or alias in a SQL query is known as aliasing. In the context of a given query, it makes it possible to refer to a different table or column, hence enables to simplify complex queries, enhance readability, and resolve naming conflicts in a query.

Table Aliasing: When utilizing table aliases, give a table in the query a temporary name. This is especially helpful when refers to a table with a long or complicated name or if need to link several tables.

Table aliasing's fundamental syntax is as follows: SELECT alias.column_name FROM table_name AS alias;

Consider the following scenario:

Extract the names of the employees along with the names of their departments from two tables, "Employees" and "Departments," for instance.

Table aliases can be used to make the query simpler:

SELECT emp.name, dep.name

FROM Employees AS emp JOIN Departments AS dep ON emp.department_id = dep.id;

In this illustration, "emp" and "dep" are the table aliases for the corresponding "Employees" and "Departments" tables.

Column aliasing: Columns in the query result are given temporary names using column aliases. This can be helpful when to add computations or functions to the columns or modify the name of a column in the result set. Column aliasing has the following syntax:

SELECT column_name AS alias FROM table_name;

Here is an example where the average salary is calculated and the alias "avg_salary" is used in the search result:

SELECT AVG(salary) AS avg_salary

FROM Employees;

The result in this scenario will include a column called "avg_salary" that contains the estimated average salary. Column aliases can also be used to give columns names that are more meaningful or descriptive, which makes the query result easier to read.