Solve the callback hell problem when exporting a value in SQL query

Question

My goal is to set someVar to 1 if my SQL query finds a result. The problem is, the assignment is local, and when I try to use console.log(someVar), the result is 1 inside the block, but 0 outside the block. Is there a way to export the values ​​outside the block?

let someVar = 0;
con.query(`SOME SQL QUERY`, (error, rows) => {
    if (error) throw error
    if (rows.length > 0) {
        someVar = 1;
        //console.log(someVar) -> The result is 1
    }
});
con.end();
//console.log(someVar) -> The result is 0

if (someVar === 0) {
    //Some code
}

Answer 1

Thanks to Fredrik, I fixed it. I ended up using the following promise

let promiseQuery = await new Promise((resolve, reject) => {
    con.query(`SOME SQL QUERY`, (error, results, fields) => {
        if (error) reject(error);
        resolve(results || {});
    })

})
const someVar = promiseQuery.length
if (someVar === 0) {
    // Some code
} else {
    // Some code
}