CREATE TABLE IF NOT EXISTS `user_info` (
 `id` int(11) NOT NULL AUTO_INCREMENT COMMENT '自增主键',
 `name` varchar(255) NOT NULL default '' COMMENT '姓名',
 `age` int(11) NOT NULL default '0' COMMENT '年龄',
 PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COMMENT='用户信息表';

$arr = [	
	[
		'name' => 'testname1',
		'age' => 18,
	],
	[
		'name' => 'testname2',
		'age' => 19,
	],
	[
		'name' => 'testname3',
		'age' => 18,
	],
];

$servername = "localhost";
$port = 3306;
$username = "username";
$password = "password";
$dbname = "mytestdb";

// 创建连接
$conn = new mysqli($servername, $username, $password, $dbname, $port);

// 检测连接
if ($conn->connect_error) {
 die("connect failed: " . $conn->connect_error);
} 

$costBegin = microtime(true);

foreach($arr as $item) {
 	$sql = sprintf("INSERT INTO user_info (name, age) VALUES ( '%s', %d);", $item['name'], (int)$item['age']);	 
	if ($conn->query($sql) === TRUE) {
	 echo "insert success";
	} else {
	 echo "Error: " . $sql . "<br>" . $conn->error;
	}
}

$costEnd = microtime(true);
$cost = round($costEnd - $costBegin, 3);
var_dump($cost);

$conn->close();

$arr = [	
	[
		'name' => 'testname1',
		'age' => 18,
	],
	[
		'name' => 'testname2',
		'age' => 19,
	],
	[
		'name' => 'testname3',
		'age' => 18,
	],
	// 此处省略
	……
	……
];

$servername = "localhost";
$port = 3306;
$username = "username";
$password = "password";
$dbname = "mytestdb";

// 创建连接
$conn = new mysqli($servername, $username, $password, $dbname, $port);

// 检测连接
if ($conn->connect_error) {
 die("connect failed: " . $conn->connect_error);
} 

$costBegin = microtime(true);

if (!empty($arr)) {
	$sql = sprintf("INSERT INTO user_info (name, age) VALUES ");

	foreach($arr as $item) {
  $itemStr = '( ';
  $itemStr .= sprintf("'%s', %d", $item['name'], (int)$item['age']);
  $itemStr .= '),';
  $sql .= $itemStr;
  }

 // 去除最后一个逗号，并且加上结束分号
 $sql = rtrim($sql, ',');
 $sql .= ';';

	if ($conn->query($sql) === TRUE) {
	} else {
	 echo "Error: " . $sql . "<br>" . $conn->error;
	}
}

$costEnd = microtime(true);
$cost = round($costEnd - $costBegin, 3);
var_dump($cost);

$conn->close();