您可以执行类似的操作：here reference link:1.stack 2.documents，nodedbconnection

var connection;
function createConnectionDB (host,dbName,userName,password) {
   connection[dbName] = mysql.createConnection({
    host     : host,
    user     : userName,
    password : password,
    database : dbName
  });
  connection[dbName].connect();
};

  // In API when You getting DBName 'db1' you can use
  createConnectionDB('localhost','db1','username','password')
  connection['db1'].query('SELECT * from < table name >', function(err, rows, fields) {
    if (!err)
      console.log('The solution is: ', rows);
    else
      console.log('Error while performing Query.');
  });
  connection['db1'].end();

  ////So API when You getting DBName ('db2') you can use
  createConnectionDB('localhost','db2','username','password')
  connection['db2'].query('SELECT * from < table name >', function(err, rows, fields) {
    if (!err)
      console.log('The solution is: ', rows);
    else
      console.log('Error while performing Query.');
  });
  connection['db2'].end();