Node.js - PostgreSQL SUM()

In this article, we would like to show you how to use SQL SUM() function in Node.js.

Note: at the end of this article you can find database preparation SQL queries.

async/await example:

const { Client } = require('pg');

const client = new Client({
    host: '127.0.0.1',
    user: 'postgres',
    database: 'database_name',
    password: 'password',
    port: 5432,
});

const execute = async (query) => {
    try {
        await client.connect();                     // creates connection
        const { rows } = await client.query(query); // sends query
        console.log(rows);
    } catch (error) {
        console.log(error.stack);
    } finally {
        await client.end();                         // closes connection
    }
};

execute('SELECT SUM("salary") AS "salary_sum" FROM "users"');

Output: 

[ { "salary_sum": 29050 } ]

Database preparation

create_tables.sql file:

CREATE TABLE "users" (
	"id" SERIAL NOT NULL,
	"name" VARCHAR(50) NOT NULL,
	"surname" VARCHAR(50) NOT NULL,
	"department_id" INTEGER NULL,
    "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');