python 数据库查询返回list或tuple实例

MySQLdb默认查询结果都是返回tuple，输出时候不是很方便，必须按照0，1这样读取，无意中在网上找到简单的修改方法，就是传递一个cursors.DictCursor就行。

默认程序：

import MySQLdb

db = MySQLdb.connect(host='localhost', user='root', passwd='123456', db='test')

cur = db.cursor()

cur.execute('select * from user')

rs = cur.fetchall()

print rs

# 返回类似如下

# ((1000L, 0L), (2000L, 0L), (3000L, 0L))

修改后：

import MySQLdb

import MySQLdb.cursors

db = MySQLdb.connect(host='localhost', user='root', passwd='123456', db='test',

cursorclass=MySQLdb.cursors.DictCursor)

cur = db.cursor()

cur.execute('select * from user')

rs = cur.fetchall()

print rs

# 返回类似如下

# ({'age': 0L, 'num': 1000L}, {'age': 0L, 'num': 2000L}, {'age': 0L, 'num': 3000L})

或者也可以用下面替换connect和cursor部分

db = MySQLdb.connect(host='localhost', user='root', passwd='123456', db='test')

cur = db.cursor(cursorclass=MySQLdb.cursors.DictCursor)

我的实践：

输出为元组类型：

import pymysql

db = pymysql.connect("localhost", "root", "123456", "filestore")

cursor = db.cursor()

sql='select * from tablelist where id>%s' %4

#查询方法一

cursor.execute(sql)

result=cursor.fetchall()

print('result',result)

sql2='select * from tablelist where id>%s'

values=('4') # 此处为元组类型

#查询方法二

cursor.execute(sql2,values)

result2=cursor.fetchall()

print('result2',result2)

id_list=[]

tablename_list=[]

tabletime_lsit=[]

cursor.execute('select * from tablelist where id>%s',[4,])

result3=cursor.fetchall()

print('type(result3)',type(result3))

#对((6, 'engineeringdata20180901', '1535731200'),)类型数据的提取

for i in range(len(result3)):

id_list.append(result3[i][0])

tablename_list.append(result3[i][1])

tabletime_lsit.append(result3[i][2])

print(id_list)

print(tabletime_lsit)

print(tablename_list)

cursor.close()

db.close()

#输出结果：

result ((6, 'engineeringdata20180901', '1535731200'), (618, 'engineeringdata20180904', '1535990400'))

result2 ((6, 'engineeringdata20180901', '1535731200'), (618, 'engineeringdata20180904', '1535990400'))

type(result3) <class 'tuple'>

[6, 618]

['1535731200', '1535990400']

['engineeringdata20180901', 'engineeringdata20180904']

输出为list类型：

list_id=[]

list_tablename=[]

list_tabletime=[]

list=get_list('select * from tablelist where id>%s',[4])

print('list:',list)

# 对[{'id': 6, 'tablename': 'engineeringdata20180901', 'tabletime': '1535731200'},]类型数据的提取

for i in range(len(list)):

print(list[i])

list_id.append(list[i]['id'])

list_tablename.append(list[i]['tablename'])

list_tabletime.append(list[i]['tabletime'])

print('list_id:',list_id)

print('list_tabletime:',list_tabletime)

print('list_tablename:',list_tablename)

# 输出结果为：

list: [{'id': 6, 'tablename': 'engineeringdata20180901', 'tabletime': '1535731200'}, {'id': 618, 'tablename': 'engineeringdata20180904', 'tabletime': '1535990400'}]

{'id': 6, 'tablename': 'engineeringdata20180901', 'tabletime': '1535731200'}

{'id': 618, 'tablename': 'engineeringdata20180904', 'tabletime': '1535990400'}

list_id: [6, 618]

list_tabletime: ['1535731200', '1535990400']

list_tablename: ['engineeringdata20180901', 'engineeringdata20180904']

补充知识：python下 将 pymysql 返回的元组数据转换为列表

我就废话不多说了，大家还是直接看代码吧！

from itertools import chain

...

sql="select elems from table"

cursor.execute(sql)

elems = cursor.fetchall()

resultlist = list(chain.from_iterable(elems))

...

以上这篇python 数据库查询返回list或tuple实例就是小编分享给大家的全部内容了，希望能给大家一个参考，也希望大家多多支持。