如何调取mysql数据库

import mysql.connector

# 连接数据库
conn = mysql.connector.connect(
  host="localhost",
  user="yourusername",
  password="yourpassword",
  database="yourdatabase"
)

# 创建游标对象
cursor = conn.cursor()

# 执行查询
cursor.execute("SELECT * FROM yourtable")

# 获取结果
result = cursor.fetchall()

# 处理结果
for row in result:
  print(row)

# 关闭游标和连接
cursor.close()
conn.close()

import java.sql.*;

public class Main {
  public static void main(String[] args) {
    // 连接数据库
    try {
      String url = "jdbc:mysql://localhost:3306/yourdatabase";
      String username = "yourusername";
      String password = "yourpassword";
      Connection conn = DriverManager.getConnection(url, username, password);

      // 创建Statement对象
      Statement stmt = conn.createStatement();

      // 执行查询
      String sql = "SELECT * FROM yourtable";
      ResultSet rs = stmt.executeQuery(sql);

      // 处理结果
      while (rs.next()) {
        System.out.println(rs.getString("column_name"));
      }

      // 关闭结果集、Statement和连接
      rs.close();
      stmt.close();
      conn.close();
    } catch (SQLException e) {
      e.printStackTrace();
    }
  }
}

const mysql = require('mysql');

// 创建数据库连接
const conn = mysql.createConnection({
  host: 'localhost',
  user: 'yourusername',
  password: 'yourpassword',
  database: 'yourdatabase'
});

// 连接数据库
conn.connect((err) => {
  if (err) throw err;
  console.log('Connected to MySQL database');
});

// 执行查询
conn.query('SELECT * FROM yourtable', (err, result) => {
  if (err) throw err;
  console.log(result);
});

// 关闭数据库连接
conn.end();

<?php
$servername = "localhost";
$username = "yourusername";
$password = "yourpassword";
$dbname = "yourdatabase";

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

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

// 执行查询
$sql = "SELECT * FROM yourtable";
$result = $conn->query($sql);

// 处理结果
if ($result->num_rows > 0) {
  while($row = $result->fetch_assoc()) {
    echo $row["column_name"]. "<br>";
  }
} else {
  echo "0 results";
}

// 关闭连接
$conn->close();
?>