xdc_git_python_20210511/python_base/day9/查询数据.py

# -*- coding: UTF-8 -*-

##============  ============###

import pymysql

conn = pymysql.connect(
    host='a.xdc.ink',
    port=3306,
    user='xdc',
    passwd='Xdc123@a',
    db='cmd',
    charset='utf8mb4'
)

# 获取游标对象
# cursor = conn.cursor()
cursor = conn.cursor(cursor=pymysql.cursors.DictCursor)  # 获取的内容以字典形式显示

query_sql = "select id,name,age from t1 where name=%s" # pymysql 自有的格式
query_sql = "select id,name,age from t1 where {}=%s".format('name') # 同上

row_nums = cursor.execute(query_sql, ('xdc'))

print(row_nums)

"""
获取到数据结果具有迭代器到特效：
1、可以通过索引取值，可以切片
2、结果集中到数据每次取出一条就少一条
"""

print(cursor.fetchmany(2)) # 获取两条数据
print(cursor.fetchone()) # 获取一条数据
print(cursor.fetchall())  # 获取所有

cursor.close()
conn.close()