python操作数据之查询

import pymysql
def query(sql):
    """
    查询数据
    """
    con = pymysql.connect(
        host="**********",
        port=3306,
        user="root",
        password="*******",
        database="*****",
        charset='utf8'
    )  # 链接数据库
    cur = con.cursor() # 获取游标
    cur.execute(sql) #执行sql
    for id, instance, plan in cur.fetchmany(size=3): #查询前3个
        print(id,instance,plan)
    cur.close() # 关闭游标
    con.close() # 关闭链接
if __name__=='__main__':
    sql = "select * from plan"
    query(sql)