Node.js - MySQL SELECT DISTINCT statement

In this article, we would like to show you how to make MySQL SELECT DISTINCT statement in Node.js.

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

Practical example

const mysql = require('mysql');

const connection = mysql.createConnection({       // gets connection with database
    host: 'localhost', // '127.0.0.1'
    user: 'root',
    password: 'password',
    database: 'database_name',
});

connection.connect(error => {
    if (error) throw error;
    const query ='SELECT DISTINCT `country` FROM `users`';

    connection.query(query, (error, result) => {  // sends queries
        connection.end();                         // closes connection
        if (error) throw error;
        console.table(result);
    });
});

Result:

┌─────────┬───────────┐
│ (index) │  country  │
├─────────┼───────────┤
│    0    │  'Spain'  │
│    1    │  'Italy'  │
│    2    │ 'Vietnam' │
│    3    │ 'Poland'  │
└─────────┴───────────┘

Database preparation

create_tables.sql file:

CREATE TABLE `users` (
	`id` INT(10) UNSIGNED NOT NULL AUTO_INCREMENT,
	`name` VARCHAR(100) NOT NULL,
	`country` VARCHAR(15) NOT NULL,
	PRIMARY KEY (`id`)
)
ENGINE=InnoDB;

insert_data.sql file:

INSERT INTO `users`
	(`name`, `country`)
VALUES
    ('Tom', 'Poland'),
    ('Chris', 'Spain'),
    ('Jack', 'Spain'),
    ('Kim', 'Vietnam'),
    ('Marco', 'Italy'),
    ('Kate', 'Spain'),
    ('Nam', 'Vietnam');