调用mysql的数据库

import mysql.connector

try:
    conn = mysql.connector.connect(
        host="localhost",
        user="yourusername",
        password="yourpassword",
        database="yourdatabase"
    )
except mysql.connector.Error as err:
    print(f"Error: {err}")

cursor = conn.cursor()
query = "SELECT * FROM users WHERE username = %s AND password = %s"
cursor.execute(query, (username, password))

try:
    conn.start_transaction()
    cursor.execute("UPDATE account SET balance = balance - 100 WHERE id = 1")
    cursor.execute("UPDATE account SET balance = balance + 100 WHERE id = 2")
    conn.commit()
except:
    conn.rollback()

import mysql.connector

# 连接到数据库
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 users")

# 获取结果
results = cursor.fetchall()
for row in results:
    print(row)

# 关闭连接
cursor.close()
conn.close()