How Can Async/Await Simplify Multiple MySQL Queries in Node.js?

Asynchronous Programming with MySQL in Node.js Using Async/Await

In Node.js, asynchronous operations are widely employed to handle database interactions efficiently. The async/await syntax, introduced with Node.js 8 onwards, offers a convenient way to handle such operations in a synchronous-like manner.

Consider a scenario where you need to execute multiple queries against a MySQL database and append their results to a string. Traditionally, callbacks are used to handle asynchronous queries. However, with async/await, you can simplify and synchronize this process.

The following code demonstrates how to use the async/await keywords in Node.js to execute multiple MySQL queries and append their results:

const mysql = require('mysql'); // or use import if you use TS
const util = require('util');
const conn = mysql.createConnection({ yourHOST/USER/PW/DB });

// node native promisify
const query = util.promisify(conn.query).bind(conn);

(async () => {
  try {
    const rows1 = await query('select count(*) as count1 from file_managed');
    const rows2 = await query('select count(*) as count2 from file_managed');
    const rows3 = await query('select count(*) as count3 from file_managed');
    const rows4 = await query('select count(*) as count4 from file_managed');

    // append the results to a string
    const appendedText = `${rows1[0].count1} - ${rows2[0].count2} - ${rows3[0].count3} - ${rows4[0].count4}`;

    console.log(appendedText);
  } finally {
    conn.end();
  }
})();

In this code, the query function has been wrapped with util.promisify() to transform the callback-based function into a promise-returning function. Using the async/await syntax, you can then execute multiple queries sequentially. The results from each query are assigned to variables, and the final appended string is logged to the console.

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