How can i return a value from DB to a variable using node and mysql?

Question

I'm trying to return a value from mysql using node and a query but i got an error that says nothing to me, i believe that is something related to my query but, i don't know what, can someone please help me? I've dig in a lot of places but didn't find anything that could help me. This is the code:

let queryIdBairro = "SELECT id FROM bairros ORDER BY id DESC LIMIT 1;"
                    conn.execSQLQuery(queryIdBairro, function(result, err) {
                        if(result){
                            bairro = result[0].id

                            let cadastraFrete = "INSERT INTO fretes_bairros (idempresa, idbairro, frete, status) VALUES (" + empresa + ", " + bairro + ", " + valor + ", " + 1 + ");"
                            conn.execSQLQuery(cadastraFrete, function(err, result) {
                                if(result){
                                    console.log("[" + new Date() + "] " + "BAIRRO COM O ID "  + bairro.id + "CADASTRADO COM SUCESSO")
                                    resolve(bairro)
                                } else if(err){
                                    console.log("DEU RUIM PARA SALVAR O FRETE AMIGUINHO... [" + new Date() + "] " + err)
                                }
                            })
                        } else if(err){
                            console.log("DEU RUIM NA PRIMEIRA BUSCA DO NOVO BAIRRO AMIGUINHO... [" + new Date() + "] " + err)
                        }
                    })

In the console i got this:

[Mon Jun 29 2020 13:50:31 GMT-0300 (GMT-03:00)] [object Object]

I'm pretty new on node and have no idea about this error or how to fix it exactly. Any help will be very appreciated.

Thanks in advance.

First you need to see what is the error but you can't see it because you are trying to concatenate an object with an string. Please do a console.log(err) in an isolated line to see the error. — Ivan Lynch, Jun 29 '20 at 17:19
It looks like barrio.id is an object. What do you get when you put in console.dir(barrio.id)? Also, why are you executing a SQL query and then not using the result? — drnugent, Jun 29 '20 at 17:19
If you just want to console the data: `JSON.stringify(bairro.id)` or for err `JSON.stringify(err)` in console.log — wrangler, Jun 29 '20 at 17:34
@IvanLynch, thanks for your answer, if log err i got [object Object]... — Gabriel Sassaki, Jun 29 '20 at 17:37
@drnugent, thanks for your answer also, you're right, bairro.id was an object, i took the .id off, I'm using the result in the insert query, I'm using it wrong? Anyways, i find an answer, don't if is right but it works just don't understand why, I'll post the answer if someone can help understand I'll be very happy... — Gabriel Sassaki, Jun 29 '20 at 17:37
conn.execSQLQuery(cadastraFrete, function(result, err) { if(result){ console.log(JSON.stringify(result)) } else if(err){ console.log(JSON.stringify(err)) } }) — Ivan Lynch, Jun 29 '20 at 18:17

score 0 · Answer 1 · answered Jun 29 '20 at 17:40

Thanks everyone for your answers, i find a workaround, don't know if it's right but works and I don't know why, can someone help understand? Here's the code:

let queryIdBairro = "SELECT id FROM bairros ORDER BY id DESC LIMIT 1;"
                    conn.execSQLQuery(queryIdBairro, function(result, err) {
                        //console.log(result, err)
                        if(err){
                            bairro = err[0].id
                            let cadastraFrete = "INSERT INTO fretes_bairros (idempresa, idbairro, frete, status) VALUES (" + empresa + ", " + bairro + ", " + valor + ", " + 1 + ");"
                            conn.execSQLQuery(cadastraFrete, function(err, result) {
                                if(result){
                                    console.log("[" + new Date() + "] " + "BAIRRO COM O ID "  + bairro + " CADASTRADO COM SUCESSO")
                                    resolve(bairro)
                                } else if(err){
                                    console.log("DEU RUIM PARA SALVAR O FRETE AMIGUINHO... [" + new Date() + "] " + err)
                                }
                            })
                        } else if(result){
                            console.log("DEU RUIM NA PRIMEIRA BUSCA DO NOVO BAIRRO AMIGUINHO... [" + new Date() + "] " + err)
                        }

As you can see, I just change result and err on the if statement

Why?

Your code is **vulnerable** to **sql injection** you should always use **prepared staemente with parameters** see https://stackoverflow.com/questions/15778572/preventing-sql-injection-in-node-js — nbk, Jun 29 '20 at 17:55
@nbk, thanks for your comment, honestly, i still don't know how to perform this, but I will learn and start using it... — Gabriel Sassaki, Jun 29 '20 at 18:17

How can i return a value from DB to a variable using node and mysql?

1 Answers1