Storing a javascript object from redis inside array to MYSQL database?

I want to store my redis data to MySQL.
My Redis data array, and each data is object.

This is what I try, but cannot save to MySQL correctly.

if (redis_headline != null) {

var con = mysql.createConnection({
  host: "localhost",
  user: "root",
  password: "",
  database: "redistest"
});

con.connect(function(err) {
  if (err) throw err;
  console.log("Connected to MySQL!");
});

// redis isi
for (i = 0; i < redis_headline.length; i++) {

  var sql = "INSERT INTO `desc` (first_name, last_name, email, phone) VALUES ('" + redis_headline[i].first_name + "','" + redis_headline[i].last_name +"','" + redis_headline[i].email + "','" + redis_headline[i].phone + "')";

  con.query(sql, function (err) {
  if (err) throw err;
  console.log("record inserted");
  });

  client.flushdb( function (err, succeeded) {
  console.log(succeeded + ' flush redis'); // will be true if successfull
  });

  // var datas = 
  // console.log(redis_headline[i]);
}} else {}