php查询mysql数据库乱码

// 设置PHP脚本的字符编码为UTF-8
header("Content-Type: text/html; charset=utf-8");

// 连接MySQL数据库时指定字符编码
$mysqli = new mysqli("localhost", "user", "password", "database");
$mysqli->set_charset("utf8");

-- 查看当前数据库的字符编码
SHOW VARIABLES LIKE 'character_set_%';

-- 设置MySQL服务器的字符编码为UTF-8
ALTER DATABASE database_name CHARACTER SET utf8 COLLATE utf8_general_ci;
ALTER TABLE table_name CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci;

// 连接MySQL数据库时指定字符编码
$mysqli = new mysqli("localhost", "user", "password", "database");
$mysqli->set_charset("utf8mb4");