npm install mysql --save-dev

// test.js
var mysql = require('mysql');

// test.js
var mysql = require('mysql');

// 创建连接
var conn = mysql.createConnection({
 host : '127.0.0.1',
 user : 'root',
 password : '123',
 database : 'test'
});

// 创建连接后不论是否成功都会调用
conn.connect(function(err){
 if(err) throw err;
 console.log('connect success!');
});

// 其他的数据库操作，位置预留

// 关闭连接时调用
conn.end(function(err){
 if(err) throw err;
 console.log('connect end');
})

$ node test.js
connect success!
connect end

conn.query('SELECT * FROM `user`', function(err, result, fields){
 if(err) throw err;
 console.log(result);
});
console.log( 'select ended!' );

select ended! // 先输出

[
 RowDataPacket {   
 uid: 1,   
 username: 'meizi',  
 password: 'meizi
 email: '123@qq.com'
 }, 
 RowDataPacket {   
 uid: 2,   
 username: 'test',  
 password: 'test
 email: '456@qq.com'
 }
]

console.log(result[0].username); // meizi 

INSERT INTO table_name ( field1, field2,...fieldN ) VALUES ( value1, value2,...valueN );

INSERT INTO table_name SET field1=value1, field2=value2, ... fieldN=valueN;

conn.query("INSERT INTO `user` SET `username`='qwerty', `password`='741', `email`='qwerty@qq.com'", function(err, result){
 if(err) throw err;
 console.log(result);
});

OkPacket {    
 fieldCount: 0,  
 affectedRows: 1,
 insertId: 4, // 数据插入成功时，对应的主键id
 serverStatus: 2,  
 warningCount: 0,  
 message: '',   
 protocol41: true,  
 changedRows: 0
 }

// 更新uid的密码
conn.query('UPDATE `user` SET `password`="123456" WHERE `uid`=4', function(err, result){
 if(err) throw err;
 console.log(result);
});

OkPacket {
 fieldCount: 0,
 affectedRows: 1,
 insertId: 0,
 serverStatus: 2,
 warningCount: 0,
 message: '(Rows matched: 1 Changed: 1 Warnings: 0',
 protocol41: true,
 changedRows: 1
 }

conn.query('DELETE FROM `user` WHERE `uid`=4', function(err, result, fields){
 if(err) throw err;
 console.log(result);
});

OkPacket {
 fieldCount: 0,
 affectedRows: 1,
 insertId: 0,
 serverStatus: 2,
 warningCount: 0,
 message: '',
 protocol41: true,
 changedRows: 0
 }

// test.js
var mysql = require('mysql');

var pool = mysql.createPool({
 host : '127.0.0.1',
 user : 'root',
 password : '123',
 database : 'test'
})

pool.query('SELECT * FROM `user`', function(err, result){
 if(err) throw err;

 console.log(result);

 pool.end(function(err){
  if(err) throw err;
  console.log('connection ended');
 })
});

// test.js
var mysql = require('mysql');

var pool = mysql.createPool({
 host : '127.0.0.1',
 user : 'root',
 password : '123',
 database : 'test'
})

pool.getConnection(function(err, connection){
 if(err) throw err;

 connection.query('SELECT * FROM `user`', function(err, result){
  if(err) throw err;

  console.log(result);
 })
});

pool.getConnection(function(err, connection){
 if(err) throw err;

 connection.query('SELECT * FROM `user`', function(err, result){
  if(err) throw err;

  console.log(result);
  connection.release();
  // 接下来connection已经无法使用，它已经被返回到连接池中 
 })
});

pool.on('connection', function (connection) {
 console.log('new connection');
});

pool.query('SELECT SQL_CALC_FOUND_ROWS * FROM `user`');
pool.query('SELECT FOUND_ROWS()');

var sql = 'SELECT * FROM `user` WHERE `uid`='+connection.escape('"123";//--');
console.log(sql); // SELECT * FROM `user` WHERE `uid`='\"123\";//--'

connection.query(sql, function(err, result){
 if(err) throw err;

 console.log(result);
})

var sql = 'SELECT * FROM '+connection.escapeId('user')+' WHERE `uid`=1';
connection.query(sql, function(err, result){
 console.log(result);
})
console.log(query.sql); // SELECT * FROM `user` WHERE `uid`=1

var params = ['test', 'test'];
var query = connection.query('SELECT * FROM `user` WHERE `username`=? AND `password`=?', params, function(err, result){
 console.log(result);
});
console.log(query.sql); // SELECT * FROM `user` WHERE `username`='test' AND `password`='test'

var params = {username:'qwerty', password:'qwerty', email:'qwerty@qq.com'};
var query = connection.query('INSERT INTO `user` SET ?', params, function(err, result){
 if(err) throw err;
 console.log(result);
});
console.log(query.sql); // INSERT INTO `user` SET `username` = 'qwerty', `password` = 'qwerty', `email` = 'qwerty@qq.com'

var params = ['user', 'username', 'test', 'password', 'test'];
var query = connection.query('SELECT * FROM ?? WHERE ??=? AND ??=?', params, function(err, result){
 console.log(result);
})
console.log(query.sql); // SELECT * FROM `user` WHERE `username`='test' AND `password`='test'

var userId = 1;
var sql = "SELECT * FROM ?? WHERE ?? = ?";
var inserts = ['user', 'uid', userId];
sql = mysql.format(sql, inserts); // SELECT * FROM `user` WHERE `uid` = 1

var connection = mysql.createConnection({multipleStatements: true});

connection.query('SELECT 1; SELECT 2', function(err, results) {
 if (err) throw err;

 // `results`是一个包含多个语句查询结果的数组
 console.log(results[0]);
 console.log(results[1]);
});