AS

MySQL

Example

SELECT firstname AS Name, age AS Age FROM users;

Output

Name	Age
Peter	23
John	30
Jane	25

Explanation

In the given SQL query, “AS” is used to rename the columns in the output. The column “firstname” is displayed as “Name” and the column “age” as “Age”.

PostgreSQL

Example

CREATE TABLE Employees (
    id INT PRIMARY KEY,
    name VARCHAR,
    salary FLOAT
);

INSERT INTO Employees
VALUES (1, 'John Doe', 50000),
       (2, 'Jane Smith', 60000),
       (3, 'Mike Johnson', 55000);

SELECT name AS Employee_Name, salary AS Employee_Salary
FROM Employees;

Output

| Employee_Name  | Employee_Salary |
|----------------|-----------------|
| John Doe       | 50000           |
| Jane Smith     | 60000           |
| Mike Johnson   | 55000           |

Explanation

In the given SQL code, a table named ‘Employees’ is created with three columns - ‘id’, ‘name’, and ‘salary’. Three rows are inserted into the table with different employee records. The ‘SELECT’ statement is then used with the ‘AS’ keyword to rename ‘name’ column as ‘Employee_Name’ and ‘salary’ column as ‘Employee_Salary’. The ‘AS’ keyword in SQL is used to rename a column or table with an alias. The output section shows the result of the select query.

SQL Server

Example

SELECT first_name AS Name
FROM employee;

Output

Name
-----
John
Jane
Kate
Smith

Explanation

In this SQL statement, it selects a column “first_name” from the table “employee”. The “AS” keyword is used to rename the output header “first_name” to “Name”.

Oracle

Example

SELECT first_name AS "Name", age AS "Age" FROM employees;

Output

Name	Age
John Doe	30
Jane Doe	25
Amanda Smith	32
David James	27

Explanation

In this example, the AS keyword is used to rename the columns in the result set. The first_name column is renamed to Name and the age column is renamed to Age.

SQLite

Example

CREATE TABLE Users (
    ID INT PRIMARY KEY,
    Name TEXT,
    Age INT
);

INSERT INTO Users (ID, Name, Age)
VALUES (1, 'John Doe', 30),
       (2, 'Jane Doe', 25),
       (3, 'Roe Doe', 40);

SELECT Name AS 'User Name', Age AS 'User Age'
FROM Users;

Output

| User Name | User Age |
|-----------|----------|
| John Doe  |   30     |
| Jane Doe  |   25     |
| Roe Doe   |   40     |

Explanation

In SQL, the AS keyword is primarily used to rename columns or tables with an alias. In the given example, the query renames the columns ‘Name’ and ‘Age’ as ‘User Name’ and ‘User Age’, respectively. The alias name is used to enhance query readability and results interpretation.