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Node.js - MySQL SELECT DISTINCT statement
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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.
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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: 'password',
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database: 'database_name',
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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 DISTINCT `country` FROM `users`';
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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) │ country │
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├─────────┼───────────┤
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│ 0 │ 'Spain' │
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│ 1 │ 'Italy' │
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│ 2 │ 'Vietnam' │
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│ 3 │ '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');