Node.js MySQL Update Statement

Node.js is an open-source platform for executing JavaScript code on the server-side. It can be downloaded from here. MySQL is an open-source Relational Database Management System (RDBMS) that uses Structured Query Language (SQL). It is the most popular language for adding, accessing, and managing content in a database. Here we will use the MySQL as a database for our node application. It can be downloaded from here.

Update statement: Update command is a DML command which is used for manipulating the records of a table.

Syntax:

UPDATE [table_name] SET column_A = value_A, 
  column_B = value_B, ... WHERE condition

Modules:

• mysql: mysql module is used for interaction between the MySQL server and the node.js application.

Installing module:

npm install mysql

SQL publishers Table preview:

Example 1: Update all salary to 0.

index.js

// Importing module
const mysql = require("mysql");

// Creating connection
let db_con  = mysql.createConnection({
    host: "localhost",
    user: "root",
    password: '',
    database: 'gfg_db'
});

db_con.connect((err) => {
    if (err) {
      console.log("Database Connection Failed !!!", err);
      return;
    }

    console.log("We are connected to gfg_db database");

    // Creating Query
    let query = "UPDATE publishers SET salary=0";

    // Executing Query
    db_con.query(query, (err, rows) => {
        if(err) throw err;
        console.log(rows);
    });
});

Run index.js file using below command:

node index.js

Console Output: Using the Where clause is very important in UPDATE. Otherwise, the whole table may become useless.

Example 2: Increase the salary of publishers by 1000 who are earning more than 7000.

index.js

// Importing module
const mysql = require("mysql");

// Creating connection
let db_con  = mysql.createConnection({
    host: "localhost",
    user: "root",
    password: '',
    database: 'gfg_db'
});

db_con.connect((err) => {
    if (err) {
      console.log("Database Connection Failed !!!", err);
      return;
    }

    console.log("We are connected to gfg_db database");

    // Generating Query
    let query =
"UPDATE publishers SET salary=salary+1000 WHERE salary > 7000";

    // Executing Query
    db_con.query(query, (err, rows) => {
        if(err) throw err;

        console.log(rows);
    });
});

Run index.js file using below command:

node index.js

Console Output: Notice previous and current salary of users with id 6, 8