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Node.js - PostgreSQL FULL OUTER Join

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Created by:

Broncono

466

In this article, we would like to show you how to use SQL FULL OUTER JOIN in Node.js.

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

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const { Client } = require('pg');
​
const client = new Client({
    host: '127.0.0.1',
    user: 'postgres',
    database: 'database_name',
    password: 'password',
    port: 5432,
});
​
const fetchUserDepartments = async () => {
    const query = `SELECT * 
                   FROM "users" 
                   FULL OUTER JOIN "departments" ON "departments"."id" = "users"."department_id"`;
    try {
        await client.connect();                     // gets connection
        const { rows } = await client.query(query); // sends queries
        console.table(rows);
    } catch (error) {
        console.error(error.stack);
    } finally {
        await client.end();                         // closes connection
    }
};
​
fetchUserDepartments();

Output:

Database preparation

Edit

create_tables.sql file:

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CREATE TABLE "departments" (
    "id" SERIAL,
    "department_name" VARCHAR(50) NOT NULL,
    "location" VARCHAR(50) NULL,
    PRIMARY KEY ("id")
);
​
CREATE TABLE "users" (
    "id" SERIAL,
    "name" VARCHAR(50) NOT NULL,
    "surname" VARCHAR(50) NOT NULL,
    "department_id" INTEGER,
    PRIMARY KEY ("id"),
    FOREIGN KEY ("department_id") REFERENCES "departments" ("id")
);

insert_data.sql file:

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INSERT INTO "departments"
    ("id", "department_name", "location")
VALUES
    (1, 'Sales', 'New York'),
    (2, 'Finance', NULL),
    (3, 'HR', 'Atlanta'),
    (4, 'Purchase', 'New Orlean'),
    (5, 'Operations', 'Boston');
​
INSERT INTO "users"
    ( "name", "surname", "department_id")
VALUES
    ('John', 'Stewart', 1),
    ('Chris', 'Brown', 2),
    ('Kate', 'Lewis', 3),
    ('Ailisa', 'Gomez', NULL),
    ('Gwendolyn', 'James', 2),
    ('Simon', 'Collins', 4),
    ('Taylor', 'Martin', 2),
    ('Andrew', 'Thompson', NULL);