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PostgreSQL - Aliases

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Created by:
Dirask Admin - MR
1340

In this article, we would like to show you how to use aliases in PostgreSQL.

Quick solution:

SELECT "column_name" AS "alias_name"
FROM "table_name";

Aliases are used to give a table or a column in the table a temporary name to make it more readable. They only exist for the duration of a query.

We create aliases using AS keyword.

Practical example

To show how aliases work, we will use the following table:

PostgreSQL - example data used to present aliases
PostgreSQL - example data used to present aliases

Note:

At the end of this article you can find database preparation SQL queries.

Example 1

In this example, we will display the average salary.

Query:

SELECT AVG("salary") AS "average_salary"
FROM "users";

Output:

PostgreSQL - alias example
PostgreSQL - alias example

Example 2

In this example, we will display the number of users.

Query:

SELECT COUNT(*) AS "number_of_users"
FROM "users";

Output:

PostgreSQL - alias example
PostgreSQL - alias example

Database preparation

create_tables.sql file:

CREATE TABLE "users" (
    "id" SERIAL,
    "name" VARCHAR(50) NOT NULL,
    "surname" VARCHAR(50) NOT NULL,
    "department_id" INTEGER,
    "salary" DECIMAL(15,2) NOT NULL,
    PRIMARY KEY ("id")
);

insert_data.sql file:

INSERT INTO "users"
    ( "name", "surname", "department_id", "salary")
VALUES
    ('John', 'Stewart', 1, '3512.00'),
    ('Chris', 'Brown', 2, '1344.00'),
    ('Kate', 'Lewis', 3, '6574.00'),
    ('Ailisa', 'Gomez', NULL, '6500.00'),
    ('Gwendolyn', 'James', 2, '4200.00'),
    ('Simon', 'Collins', 4, '3320.00'),
    ('Taylor', 'Martin', 2, '1500.00'),
    ('Andrew', 'Thompson', NULL, '2100.00');

PostgreSQL

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