如何通过 mysql_insert_id 获取插入数据的自增ID？

gitbox 2025-08-27
<span><span><span class="hljs-meta">&lt;?php</span></span><span>
</span><span><span class="hljs-comment">// 以下是与文章内容无关的前置 PHP 代码示例</span></span><span>
</span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"准备开始执行数据库操作...\n"</span></span><span>;
</span><span><span class="hljs-variable">$servername</span></span><span> = </span><span><span class="hljs-string">"localhost"</span></span><span>;
</span><span><span class="hljs-variable">$username</span></span><span> = </span><span><span class="hljs-string">"root"</span></span><span>;
</span><span><span class="hljs-variable">$password</span></span><span> = </span><span><span class="hljs-string">""</span></span><span>;
</span><span><span class="hljs-variable">$dbname</span></span><span> = </span><span><span class="hljs-string">"testdb"</span></span><span>;

</span><span><span class="hljs-comment">// 创建连接</span></span><span>
</span><span><span class="hljs-variable">$conn</span></span><span> = </span><span><span class="hljs-keyword">new</span></span><span> </span><span><span class="hljs-title function_ invoke__">mysqli</span></span><span>(</span><span><span class="hljs-variable">$servername</span></span><span>, </span><span><span class="hljs-variable">$username</span></span><span>, </span><span><span class="hljs-variable">$password</span></span><span>, </span><span><span class="hljs-variable">$dbname</span></span><span>);

</span><span><span class="hljs-comment">// 检查连接</span></span><span>
</span><span><span class="hljs-keyword">if</span></span><span> (</span><span><span class="hljs-variable">$conn</span></span><span>-&gt;connect_error) {
    </span><span><span class="hljs-keyword">die</span></span><span>(</span><span><span class="hljs-string">"连接失败: "</span></span><span> . </span><span><span class="hljs-variable">$conn</span></span><span>-&gt;connect_error);
}
</span><span><span class="hljs-meta">?&gt;</span></span><span>

&lt;hr&gt;

</span><span><span class="hljs-meta">&lt;?php</span></span><span>
<span class="hljs-comment">/**
 * 文章标题: 如何通过 mysql_insert_id 获取插入数据的自增ID？
 *
 * 在使用 MySQL 数据库进行数据插入操作时，经常需要获取刚刚插入记录的自增 ID（AUTO_INCREMENT）。
 * 在 PHP 中，可以通过 `mysql_insert_id()` 或 MySQLi、PDO 提供的类似方法来实现。
 *
 * 1. 使用 MySQLi 扩展
 *
 * 通过 MySQLi 扩展执行插入操作后，可以使用 `$conn-&gt;insert_id` 获取自增 ID。
 */</span>

</span><span><span class="hljs-variable">$sql</span></span><span> = </span><span><span class="hljs-string">"INSERT INTO users (username, email) VALUES ('Alice', '[email protected]')"</span></span><span>;

</span><span><span class="hljs-keyword">if</span></span><span> (</span><span><span class="hljs-variable">$conn</span></span><span>-&gt;</span><span><span class="hljs-title function_ invoke__">query</span></span><span>(</span><span><span class="hljs-variable">$sql</span></span><span>) === </span><span><span class="hljs-literal">TRUE</span></span><span>) {
    </span><span><span class="hljs-variable">$last_id</span></span><span> = </span><span><span class="hljs-variable">$conn</span></span><span>-&gt;insert_id;
    </span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"新记录插入成功，ID 为: "</span></span><span> . </span><span><span class="hljs-variable">$last_id</span></span><span>;
} </span><span><span class="hljs-keyword">else</span></span><span> {
    </span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"插入错误: "</span></span><span> . </span><span><span class="hljs-variable">$conn</span></span><span>-&gt;error;
}

<span class="hljs-comment">/**
 * 2. 使用 PDO 扩展
 *
 * PDO 提供了 `lastInsertId()` 方法来获取上一次插入操作的自增 ID。
 */</span>

</span><span><span class="hljs-keyword">try</span></span><span> {
    </span><span><span class="hljs-variable">$pdo</span></span><span> = </span><span><span class="hljs-keyword">new</span></span><span> </span><span><span class="hljs-title function_ invoke__">PDO</span></span><span>(</span><span><span class="hljs-string">"mysql:host=<span class="hljs-subst">$servername</span></span></span><span>;dbname=</span><span><span class="hljs-subst">$dbname</span></span><span>", </span><span><span class="hljs-variable">$username</span></span><span>, </span><span><span class="hljs-variable">$password</span></span><span>);
    </span><span><span class="hljs-variable">$pdo</span></span><span>-&gt;</span><span><span class="hljs-title function_ invoke__">setAttribute</span></span><span>(PDO::</span><span><span class="hljs-variable constant_">ATTR_ERRMODE</span></span><span>, PDO::</span><span><span class="hljs-variable constant_">ERRMODE_EXCEPTION</span></span><span>);

    </span><span><span class="hljs-variable">$stmt</span></span><span> = </span><span><span class="hljs-variable">$pdo</span></span><span>-&gt;</span><span><span class="hljs-title function_ invoke__">prepare</span></span><span>(</span><span><span class="hljs-string">"INSERT INTO users (username, email) VALUES (:username, :email)"</span></span><span>);
    </span><span><span class="hljs-variable">$stmt</span></span><span>-&gt;</span><span><span class="hljs-title function_ invoke__">execute</span></span><span>([</span><span><span class="hljs-string">':username'</span></span><span> =&gt; </span><span><span class="hljs-string">'Bob'</span></span><span>, </span><span><span class="hljs-string">':email'</span></span><span> =&gt; </span><span><span class="hljs-string">'[email protected]'</span></span><span>]);

    </span><span><span class="hljs-variable">$lastId</span></span><span> = </span><span><span class="hljs-variable">$pdo</span></span><span>-&gt;</span><span><span class="hljs-title function_ invoke__">lastInsertId</span></span><span>();
    </span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"\n使用 PDO 插入记录，新记录 ID 为: "</span></span><span> . </span><span><span class="hljs-variable">$lastId</span></span><span>;
} </span><span><span class="hljs-keyword">catch</span></span><span> (PDOException </span><span><span class="hljs-variable">$e</span></span><span>) {
    </span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"错误: "</span></span><span> . </span><span><span class="hljs-variable">$e</span></span><span>-&gt;</span><span><span class="hljs-title function_ invoke__">getMessage</span></span><span>();
}

<span class="hljs-comment">/**
 * 3. 注意事项
 *
 * - `mysql_insert_id()` 是早期 MySQL 扩展中的函数，已不推荐使用，建议使用 MySQLi 或 PDO。
 * - 自增 ID 是针对表的 AUTO_INCREMENT 字段生成的唯一整数。
 * - 获取自增 ID 必须在同一个数据库连接中进行，否则可能获取不到正确值。
 * - 如果插入失败或未插入自增字段，获取的 ID 可能为 0。
 */</span>

</span><span><span class="hljs-variable">$conn</span></span><span>-&gt;</span><span><span class="hljs-title function_ invoke__">close</span></span><span>();
</span><span><span class="hljs-meta">?&gt;</span></span><span>
</span></span>
mysql_insert_id