Returning SQL query results as a variable in node.js

Question

I'm trying to grab the results of an SQL query in order to use it elsewhere in my code, but I just can't figure out how to get them out. I have nested functions so I tried to get it out through two calls of return, but what comes out isn't valid.

var users = getUsers();


function getUsers(req, res){
  dbConnect(req,res);
  return connection.query('SELECT * FROM USERS', function selectAll(err, rows, fields) {
    if (err) {
        throw err;
    }
    for (var i in rows) {
        console.log(rows[i]);
    }
    return rows;
    dbClose(req,res);
  })
}

What's wrong here?

Answer 1

connection.query is an asynchronous function.

rows is only available within the selectAll function. If you'd like to do something with the rows, you need to do it from selectAll .

users will be undefined because the function getUsers itself does not return anything (and can not return rows.

Instead of doing

users = get Users();
doSomethingWithUsers(users);

do this instead:

getUsers();

function getUsers(req, res){
  dbConnect(req,res);
  return connection.query('SELECT * FROM USERS', function selectAll(err, rows, fields) {
    if (err) {
        throw err;
    }
    for (var i in rows) {
        console.log(rows[i]);
    }
    doSomethingWithUsers(rows);
    dbClose(req,res);
  })
}

Or pass a callback function in getUsers that gets passed the result.