How to get a value from mysql query outside the query statement?

Question

Here is the function see below console.log

function quo (value){
    value = connection.query(
       \'SELECT role from `roles` where `id` = 1\' , 
       fu         


        

Answer 1

function quo (success){
    value = connection.query(
       'SELECT role from `roles` where `id` = 1' , 
       function (error, results, fields) {
           if (error) throw error;
           console.log('The role is: ', results[0].role);
           success (results[0].role);
       });
}

quo (function (role) {
   console.log(role);
   /* do something useful with the role that came back from the query */
});

Answer 2

tl;dr everything happens in a callback.

You're tripping up on the asynchronous nature of Javascript. By the time your console.log(value); call runs, the query is not (necessarily) completed. So, there's no way for the result of the query to be available at that time.

Many developers use a pattern like this, with a callback function to handle the next step when the query result arrives.

function quo (success){
    value = connection.query(
       'SELECT role from `roles` where `id` = 1' , 
       function (error, results, fields) {
           if (error) throw error;
           console.log('The role is: ', results[0].role);
           success (results[0].role);
       });
}

quo (function (role) {
   console.log(role);
   /* do something useful with the role that came back from the query */
});

Promise objects make this sort of thing easier to read in node.js. But explaining them is beyond the scope of a Stack Overflow answer anyhow.