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Node.js - MySQL GROUP BY
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In this article, we would like to show you how to use MySQL GROUP BY in Node.js.

Note: at the end of this article you can find database preparation SQL queries.
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const mysql = require('mysql');
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const connection = mysql.createConnection({ // gets connection with database
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host: 'localhost', // '127.0.0.1'
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user: 'root',
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password: '',
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database: 'test',
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});
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connection.connect(error => {
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if (error) throw error;
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const query ='SELECT COUNT(`id`) AS `number of users`, `country` ' +
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'FROM `users` ' +
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'GROUP BY `country` ' +
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'ORDER BY COUNT(`id`) DESC;';
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connection.query(query, (error, result) => { // sends queries
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connection.end(); // closes connection
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if (error) throw error;
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console.table(result);
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});
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});
Result:
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┌─────────┬─────────────────┬───────────┐
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│ (index) │ number of users │ country │
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├─────────┼─────────────────┼───────────┤
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│ 0 │ '3' │ 'Spain' │
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│ 1 │ '2' │ 'Vietnam' │
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│ 2 │ '1' │ 'Italy' │
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│ 3 │ '1' │ 'Poland' │
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└─────────┴─────────────────┴───────────┘
create_tables.sql
file:
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CREATE TABLE `users` (
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`id` INT(10) UNSIGNED NOT NULL AUTO_INCREMENT,
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`name` VARCHAR(100) NOT NULL,
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`country` VARCHAR(15) NOT NULL,
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PRIMARY KEY (`id`)
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)
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ENGINE=InnoDB;
insert_data.sql
file:
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INSERT INTO `users`
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(`name`, `country`)
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VALUES
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('Tom', 'Poland'),
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('Chris', 'Spain'),
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('Jack', 'Spain'),
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('Kim', 'Vietnam'),
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('Marco', 'Italy'),
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('Kate', 'Spain'),
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('Nam', 'Vietnam');