php中mysql中in的作用

<?php
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "database_name";

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

// 检查连接
if ($conn->connect_error) {
    die("连接失败: " . $conn->connect_error);
}

// 使用 IN 操作符
$sql = "SELECT id, name FROM users WHERE id IN (1, 3, 5)";
$result = $conn->query($sql);

if ($result->num_rows > 0) {
    // 输出数据
    while($row = $result->fetch_assoc()) {
        echo "id: " . $row["id"]. " - Name: " . $row["name"]. "<br>";
    }
} else {
    echo "0 结果";
}
$conn->close();
?>

CREATE TEMPORARY TABLE temp_ids (id INT);
INSERT INTO temp_ids (id) VALUES (1), (3), (5);

SELECT users.id, users.name
FROM users
JOIN temp_ids ON users.id = temp_ids.id;

SELECT id, name FROM users WHERE id IN ('1', '3', '5'); -- 错误，id 应该是整数类型
SELECT id, name FROM users WHERE id IN (1, 3, 5); -- 正确