You can use the JDBC service of Google Apps Script to connect to any MySQL or Google Cloud SQL database. Because the Google Script will connect to Cloud SQL using one of Google’s own IP addresses, there’s no need to whitelist any IP address in your Cloud SQL console. You can run any SQL queries and iterate through the result set with the next() method.

function connectToCloudSQL() {
  var params = {
    ip: '123.12.12.122',
    user: 'root',
    password: 'labnol',
    database: 'labnol_DB',
  };

  var dbUrl = 'jdbc:mysql://' + params.ip + '/' + params.database;
  var conn = Jdbc.getConnection(dbUrl, params.user, params.password);

  var stmt = conn.createStatement();
  var sql = 'SELECT id FROM tableName';

  stmt.setMaxRows(100);

  var results = stmt.executeQuery(sql);
  var mapping = {};

  while (results.next()) {
    Logger.log(results.getString(1));
  }

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