javascript - 函数中回调函数的返回值

Question

我知道这可能是重复的，但我现在在这个问题上坐了超过 4 个小时，似乎找不到解决方案。

var mysql = require('mysql');

var con = mysql.createConnection({
  host: "ip",
  port: port,
  user: "user",
  password: "pass",
  database:"db"
});

checkDatabase(serverID){
con.query(`SELECT * FROM servers WHERE serverid LIKE ${serverID}`, function(err, res){
    if (err)  return callback(err); // Want to return false, if serverID is not found in database
    if(res.length>1)return true; // Want to return true, if results are true
});
var valid = checkDatabase("1234") // calling function 
console.log(valid) //want to have bool true or false

标签： javascriptmysqlnode.js