mysql语句如何插入含单引号或反斜杠的值详解

前言

本文主要给大家介绍了关于mysql语句插入含单引号或反斜杠值的相关内容，下面话不多说了，来一起看看详细的介绍吧

比如说有个表，它的结构是这个样子的

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();

insert failed:You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 's day!')' at line

因为INSERT INTO activity (title) VALUES ( 'happy valentine's day!');这个sql语句里面单引号不是成对的。

有时候会往数据库里面插入一些用户给的数据，很可能会出现上面这种情况，那么该如何避免呢？

要对sql里面的特殊字符进行转义。可以把$sql的那一行代码改成如下这样：

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

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

比如说中文这两个字的unicode码是\u4e2d\u6587，但是有时候插到数据库里反斜杠被吃掉了变成了u4e2du6587

看如下示例代码:

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

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

那是因为这里的\被当成转义符了，实际上要对unicode码的\再次转义，这样插入数据库的才是对的

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

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

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