mysql语句如何插入含单引号或反斜杠的值详解

CREATE TABLE `activity` (
 `id` int(11) NOT NULL AUTO_INCREMENT COMMENT 'ID',
 `title` varchar(255) NOT NULL COMMENT '活动标题',
 PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COMMENT='活动表';

$servername = "xxxxservername";
$port = 3306;
$username = "xxxusername";
$password = "xxxpwd";
$dbname = "xxxxxxdb";

// 创建连接
$conn = new mysqli($servername, $username, $password, $dbname, 8306);

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

$item['title'] = 'happy new year!';
$sql = sprintf("INSERT INTO activity (title) VALUES ( '%s');", $item['title']);
var_dump($sql);
if ($conn->query($sql) === TRUE) {
	echo "insert success\n";
} else {
 echo "insert failed:" . $conn->error;
}

$conn->close(); 

$sql = sprintf("INSERT INTO activity (title) VALUES ( '%s');", mysqli_real_escape_string($conn, $item['title']));

INSERT INTO activity (title) VALUES ( 'happy valentine\'s day!');"

$item['title'] = json_encode([
  'balbalbla' => '中文'
]);
$sql = sprintf("INSERT INTO activity (title) VALUES ( '%s');", $item['title']);

INSERT INTO activity (title) VALUES ( '{"balbalbla":"\u4e2d\u6587"}');

$item['title'] = json_encode([
  'balbalbla' => '中文'
]);
$sql = sprintf("INSERT INTO activity (title) VALUES ( '%s');", mysqli_real_escape_string($conn, $item['title']));

INSERT INTO activity (title) VALUES ( '{\"balbalbla\":\"\\u4e2d\\u6587\"}');