First of all, I'm sorry if this question already has an answer, but I've searched for this kind of question and found nothing useful.

I'm developing a NodeJS application that uses the mysql npm package to query a database. I have written several queries which are working fine with the help of promises (because that's how the SQL module works). I have no problem when query procedure function get_works (defined below) is called normally. However, when I call this procedural function in Express Router, I get strange behavior.

view.get("/works", (req, res) => {
    (async () => {
        res.json(await get_works());
    })()
});

async function get_works(offset=0,limit=6){

    let cdc_database = mysql.createConnection({
        /*Filled with credentials*/
    });
    
    const get_texts = `SELECT TEXID,TXNOM,TXRES FROM TEXTE LIMIT ${limit} OFFSET ${offset};`; // Valid request

    /*Two steps: get texts and get authors of each texts*/

    cdc_database.connect();
    const texts = await database_promise_query(cdc_database, get_texts);
    /*This await always have a correct output*/

    let text_authors = [];

    for(i = 0; i < texts.length; i++){

        get_text_authors = `SELECT AUPRE, AUNOM FROM AUTEURS,ECRIT_PAR\
        WHERE AUTEURS.AUTID=ECRIT_PAR.AUTID AND TEXID=${texts[i].TEXID};`; // Request is valid

        text_authors[i] = (await database_promise_query(cdc_database, get_text_authors));
        /*          ^^^^^^^^
        The await above returns an undefined value randomly when called through the router
        */
        if(text_authors[i] === undefined){
            console.error(`[get_works] - Server error on ${i}th text's authors`)
            text_authors[i] = [{AUPRE: "Prénom", AUNOM: "Nom"}]
        }

    }
    

    cdc_database.end();

    return works_to_JSON(texts, text_authors)
}

Sometimes, a query to the database will have no undefined values, but once there is one undefined value, all subsequent values ​​will also be undefined.

Example trace log

(1st call, 3 errors)
[
  [ RowDataPacket { AUPRE: 'xxx', AUNOM: 'xxx' } ],
  [ RowDataPacket { AUPRE: 'xxx', AUNOM: "xxx" } ],
  [ RowDataPacket { AUPRE: 'xxx', AUNOM: 'xxx' } ],
  [ { AUPRE: 'Prénom', AUNOM: 'Nom' } ],
  [ { AUPRE: 'Prénom', AUNOM: 'Nom' } ],
  [ { AUPRE: 'Prénom', AUNOM: 'Nom' } ]
]

(2nd call, no error)
[
  [ RowDataPacket { AUPRE: 'xxx', AUNOM: 'xxx' } ],
  [ RowDataPacket { AUPRE: 'xxx', AUNOM: "xxx" } ],
  [ RowDataPacket { AUPRE: 'xxx', AUNOM: 'xxx' } ],
  [ RowDataPacket { AUPRE: 'xxx', AUNOM: 'xxx' } ],
  [ RowDataPacket { AUPRE: 'xxx', AUNOM: "xxx" } ],
  [ RowDataPacket { AUPRE: 'xxx', AUNOM: 'xxx' } ],
]

This is my promise wrapper:

function database_promise_query(database, query){
    return new Promise(res => {
        database.query(query, (error, results, fields) => {
            if(error) {res(undefined); console.log(error)}
            res(results);
        })
    })
}

However, calling this function outside of the router like this works perfectly:

(async () => {
    await get_works(0, 10);
    await get_works(10, 10);
    await get_works(20, 10);
    await get_works(30, 10);
})()

Did I miss something? I think all the queries are correct as I can get the desired results, the problem may be with my async/await processing. Thanks for all the help you can provide.

Edit 1

According to @tromgy's suggestion, I rewrote the promise wrapper.

function database_promise_query(database, query){
    return new Promise((res, rej) => {
        database.query(query, (error, results, fields) => {
            if(error) {rej(error); throw new Error(error)}
            console.log("Received response", results)
            res(results);
        })
    })
}

However, the rejection never occurs (which is reasonable since there is no matching data in the database). To clean up the logs, I disabled another router for similar requests using a different database connection. Removing this router also resolved the bug. I don't know how this is possible (maybe a variable is declared global, so I would look for that kind of problem).