mysql 多字段分表

<?php
// 数据库连接
$mysqli = new mysqli("localhost", "username", "password", "database");

// 分片键
$shardKey = "user_id";

// 获取分片表名
function getShardTableName($shardKey, $shardValue, $totalShards = 4) {
    return "user_table_" . ($shardValue % $totalShards);
}

// 插入数据
$user_id = 123;
$user_name = "John Doe";
$shardTableName = getShardTableName($shardKey, $user_id);
$sql = "INSERT INTO $shardTableName (user_id, user_name) VALUES (?, ?)";
$stmt = $mysqli->prepare($sql);
$stmt->bind_param("is", $user_id, $user_name);
$stmt->execute();

// 查询数据
$user_id = 123;
$shardTableName = getShardTableName($shardKey, $user_id);
$sql = "SELECT * FROM $shardTableName WHERE user_id = ?";
$stmt = $mysqli->prepare($sql);
$stmt->bind_param("i", $user_id);
$stmt->execute();
$result = $stmt->get_result();
while ($row = $result->fetch_assoc()) {
    echo "User ID: " . $row["user_id"] . ", User Name: " . $row["user_name"] . "<br>";
}
?>