How to send multiple query results from backend to frontend in node

Question

I am making a simple check-in and check-out system for employees. In the main panel I want to show the number of hours worked per day and in another field the weekly total.

I can now show the hours per day in a table, the problem comes when I have to show the total since I make that query to the database with another query.

With the following code I perform the query and perform a render in the index view using the EJS templates.:

router.get('/', (req, res) => {
    const week = DateTime.now().weekNumber;
    conexion.query('SELECT * FROM assistance WHERE week = ?', week, (error, results) => {
        if(error){
            throw error;
        }else{
            res.render('index', {results: results});
        }
    })
});

With this code I perform the query of the total hours. but I don't know how to show it in the same index view since it is a separate query from the first one:

conexion.query('SELECT time_format(SUM(TIMEDIFF(a.exit, a.entry)), "%H:%i") AS hours from assistance a WHERE a.week = ?', week, (error, results) => {
        if(error){
            throw error;
        }else{
            return('index', {totalHours: results});
        }
    })

In this way I am trying to receive the information in the index view with EJS:

<div>
   <div>Total hours:<%= totalHours%></div>
</div>

Lawrence Cherone · Accepted Answer · 2022-03-09 13:12:26Z

1

Use try/catch async-await, then just do both queries.

router.get('/', async(req, res) => {
  const week = DateTime.now().weekNumber

  try {
    // query 1
    const totalHours = await conexion.query('SELECT time_format(SUM(TIMEDIFF(a.exit, a.entry)), "%H:%i") AS hours from assistance a WHERE a.week = ?', week)

    // query 2
    const results = await conexion.query('SELECT * FROM assistance WHERE week = ?', week)

    res.render('index', {
      totalHours,
      results
    })
  } catch {
    res.render('error-page')
  }
})

answered Mar 9, 2022 at 13:12

Lawrence Cherone

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8 Comments

adan gimenez Over a year ago

thanks for your answer Lawrence. I have been trying with your answer but it throws me an error: <ref *1> Query { _events: [Object: null prototype] { error: [Function (anonymous)], packet: [Function (anonymous)], timeout: [Function (anonymous)], end: [Function (anonymous)] },... I was researching and found an article that talks about multiple Statements is it the same or another option, you know? thanks for your support.

Lawrence Cherone Over a year ago

what is conexion? an instance of what lib?

adan gimenez Over a year ago

conexion is the connection to my MySql database. I create it with the createConnection method. then to use it in my queries I invoke the file: const conexion = require('../database/db')

adan gimenez Over a year ago

I am using express framework

Lawrence Cherone Over a year ago

stackoverflow.com/questions/62572105/…

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