Delete data from MySQL database table using Node.js

In this tutorial article, we will see how to delete data from MySQL database using Node.js. We will use where condition to delete specific records from MySQL server. 

Perform the following steps to delete data from MySQL database server.

• Step 1: First create connection between MySQL server and Node.js.
• Step 2: After database connection created, use conn.query() method to run DELETE query into MySQL database.

var query = `DELETE FROM visitors WHERE percentage < ?`;
var percentage = 50;

• After the query executed, close the connection using conn.end() method.

We have created below delete_rows.js file with full example.

const mysql = require('mysql');

const conn = mysql.createConnection({
    host: 'localhost',
    port: 3306,
    database: 'charts',
    user: 'root',
    password: 'root',
});

conn.connect((err) => {
    if (err) {
        return console.log(err.message);
    } else {
        // select query
        var query = `DELETE FROM visitors WHERE percentage < ?`;
        var percentage = 50;
        // query to database
        conn.query(query, percentage, function(err, response, result) {
            if (err) {
                return console.log(err.message);
            } else {
                console.log(response);
            }
        });
    }
    // close the connection
    conn.end();
});

Now run the file into Node server.

node delete_rows.js

The application will response with object data. In the database all records will be deleted with percentage less than 50.

OkPacket {
  fieldCount: 0,
  affectedRows: 6,
  insertId: 0,
  serverStatus: 34,
  warningCount: 0,
  message: '',
  protocol41: true,
  changedRows: 0
}

You can get number of deleted records using response.affectedRows object property.

Note: If you omit the WHERE condition, all records will be deleted.