$ npm install -S mssql

const sql = require("mssql");

const config = {
  user: "syon@hello",
  password: "mysecretstrings",
  server: "hello.database.windows.net",
  database: "hello",
  options: {
    encrypt: true // Use this if you're on Windows Azure
  }
};

(async () => {
  await sql.connect(config);
  const result = await sql.query`select * from users where id = 1`;
  console.dir(result);
  await sql.close();
})().catch(e => {
  console.warn(e);
});

const sql = require("mssql");

const config = {
  user: process.env.MSSQL_USER,
  password: process.env.MSSQL_PASSWORD,
  server: process.env.MSSQL_SERVER,
  database: process.env.MSSQL_DATABASE,
  options: {
    encrypt: true // Use this if you're on Windows Azure
  }
}

const pool1 = new sql.ConnectionPool(config);
const pool1Connect = pool1.connect();

pool1.on("error", err => {
  console.error("!! POOL ERROR !!")
  console.error(err)
});

async function echoTheNumberOnPool(arg) {
  await pool1Connect; // ensures that the pool has been created
  try {
    const req = pool1.request();
    const res = await req.query(`select ${arg} as number`);
    await new Promise(r => setTimeout(r, 3000 * Math.random()));
    const result = res.recordset[0]
    console.log(result)
    return result;
  } catch (err) {
    console.error("SQL error", err);
  }
}

;(async () => {
  console.log('---- Promise.all Start ----')
  await Promise.all([
    echoTheNumberOnPool(1),
    echoTheNumberOnPool(2),
    echoTheNumberOnPool(3),
    echoTheNumberOnPool(4),
    echoTheNumberOnPool(5),
    echoTheNumberOnPool(6),
    echoTheNumberOnPool(7),
    echoTheNumberOnPool(8),
    echoTheNumberOnPool(9),
    echoTheNumberOnPool(10),
    echoTheNumberOnPool(11),
    echoTheNumberOnPool(12),
    echoTheNumberOnPool(13),
    echoTheNumberOnPool(14),
    echoTheNumberOnPool(15)
  ])
  console.log('---- Promise.all End ----')
  await pool1.close()
})().catch(e => {
  console.warn(e);
});

$ node main.js
---- Promise.all Start ----
{ number: 5 }
{ number: 3 }
{ number: 1 }
{ number: 7 }
{ number: 10 }
{ number: 12 }
{ number: 4 }
{ number: 2 }
{ number: 13 }
{ number: 14 }
{ number: 8 }
{ number: 15 }
{ number: 6 }
{ number: 11 }
{ number: 9 }
---- Promise.all End ----