var mysql = require('mysql');

var pool  = mysql.createPool({
  connectionLimit : 10,
  host            : 'example.org',
  user            : 'bob',
  passWord        : 'secret',
  database        : 'my_db'
});

pool.getConnection(function(err, connection) {
  // 在此处处理连接错误
  connection.query('SELECT * FROM customers', function(err, rows) {
    // 在此处处理查询结果
    connection.release(); // 释放连接
  });
});

pool.getConnection(function(err, connection) {
  // 在此处处理连接错误
  connection.query('CALL getCustomers(?, ?, @total_rows, @total_pages)', [0, 10], function(err, rows) {
    if (err) throw err;

    // 执行第二个查询以获取返回值
    connection.query('SELECT @total_rows AS total_rows, @total_pages AS total_pages', function(err, rows) {
      if (err) throw err;

      var totalRows = rows[0][0].total_rows;
      var totalPages = rows[1][0].total_pages;

      console.log('Total rows: ' + totalRows);
      console.log('Total pages: ' + totalPages);

      connection.release();
    })
  });
});