mysql主从库联查

import pymysql

# 连接主库
master_conn = pymysql.connect(host='master_host', user='user', password='password', db='db')
master_cursor = master_conn.cursor()

# 连接从库
slave_conn = pymysql.connect(host='slave_host', user='user', password='password', db='db')
slave_cursor = slave_conn.cursor()

try:
    # 从主库获取部分数据
    master_cursor.execute("SELECT * FROM table WHERE condition")
    master_data = master_cursor.fetchall()

    # 从从库获取剩余数据
    slave_cursor.execute("SELECT * FROM table WHERE condition")
    slave_data = slave_cursor.fetchall()

    # 合并数据
    combined_data = master_data + slave_data

    # 处理合并后的数据
    for row in combined_data:
        print(row)

except Exception as e:
    print(f"Error: {e}")

finally:
    master_cursor.close()
    master_conn.close()
    slave_cursor.close()
    slave_conn.close()