Example showing you how to retrieve rows for plotting SQL data from IoT core

script.gs

// Replace the variables in this block with real values.
var address = '<your-server-ip-address>';
var user = 'root';
var userPwd = '<your-password>';
var db = '<your-db-name>';

var dbUrl = 'jdbc:mysql://' + address + '/' + db;

// Read up to 1000 rows of data from the table and log them.
function readFromTable() {
  var conn = Jdbc.getConnection(dbUrl, user, userPwd);

  var start = new Date();
  var stmt = conn.createStatement();
  stmt.setMaxRows(1000);
  var results = stmt.executeQuery('SELECT * FROM wifistr');
  var numCols = results.getMetaData().getColumnCount();

  var sheet = SpreadsheetApp.getActiveSheet();
  sheet.appendRow(["ID", "Time", "Wifi Strength"]);
  while (results.next()) {
    var rowArr = [];
    for (var col = 0; col < numCols; col++) {
      res = results.getString(col + 1);
      if (col == 2) {
        res=res.replace('Wifi: ',''); // can even hackily clean up db
        res=res.replace('db','');
      }
      rowArr.push(res);
    }
    sheet.appendRow(rowArr);
  }

  results.close();
  stmt.close();
}