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PostgreSQL - Select query

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Explosssive
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In this article, we would like to show you how to make SELECT query in PostgreSQL.

Quick solution:

SELECT "column1", "column2", ...
FROM "table_name";
SELECT * FROM "table_name";

Practical example

To show how the SELECT statement works, we will use the following table:

PostgreSQL - example data used with AVG() function
PostgreSQL - example data used with SELECT statement

Note:

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

Example 1

In this example, we will display all names.

Query:

SELECT "name" AS "names" FROM "users";

Output:

PostgreSQL - SELECT statement result (HeidiSQL)
PostgreSQL - SELECT statement result (HeidiSQL)

Example 2

In this example, we will display all the information about users.

Query:

SELECT * FROM "users";

Output:

PostgreSQL - SELECT statement result (HeidiSQL)
PostgreSQL - SELECT statement result (HeidiSQL)

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');
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